Please follow these steps to change the default branch from master to main:

1. Before you start the migration add your Github user to the end of the list item to avoid overlapping efforts.
2. In the majority of python repositories, @googleapis/yoshi-python is listed as the code owner in .github/CODEOWNERS. If there are additional code owners listed, please reach out to the team listed to notify them about the effort.
3. In the “Settings” section for the Github repository, rename the default branch from master to main. If you don’t see the settings section, you will need to reach out to an admin of the repository to complete this step. Once you’re in the settings section, look for the “Default branch” section under the branches tab. For example, for python-datastream, the link to the branches tab is https://github.com/googleapis/python-datastream/settings/branches
4. Search the github repo for the term master in the repository. Open a PR in the repo to replace the term master with main. We have automation which will revert changes made to templated files so we also need to add replacements in owlbot.py to replace master with main similar to this PR. See this bash script that I used to create the branch for the linked PR. Note: Once this synthtool PR is merged and the synthtool templates have propagated to the repo via owlbot, we can remove the replacements in owlbot.py added in this step.
5. Make sure that replacements are not reverted by owlbot
6. Notify a Googler to complete the remaining steps at go/python-main-branch-migration.
7. Check the box below when the repo has been successfully migrated and verified that the continuous/nightly builds pass after the migration.

• - google-api-python-client @parthea chore: migrate default branch from master to main google-api-python-client#1498
• - google-auth-library-python @parthea chore: migrate default branch from master to main google-auth-library-python#849
• - google-auth-library-python-httplib2 @parthea chore: migrate default branch from master to main google-auth-library-python-httplib2#42
• - google-auth-library-python-oauthlib @parthea chore: migrate default branch from master to main google-auth-library-python-oauthlib#148
• - google-cloudevents-python @parthea chore: migrate default branch from master to main google-cloudevents-python#71
• - google-resumable-media-python @parthea chore: migrate default branch from master to main google-resumable-media-python#260
• - python-access-approval @parthea chore: migrate default branch from master to main python-access-approval#108
• - python-access-context-manager @dandhlee docs: migrate to main branch python-access-context-manager#76
• - python-aiplatform @parthea chore: migrate default branch from master to main python-aiplatform#661
• - python-analytics-admin @parthea chore: migrate default branch from master to main python-analytics-admin#122
• - python-analytics-data @parthea chore: migrate default branch from master to main python-analytics-data#124
• - python-api-common-protos @parthea chore: migrate default branch from master to main python-api-common-protos#57
• - python-api-core @tseaver chore: migrate default branch to main python-api-core#264
• - python-api-gateway @parthea chore: migrate default branch from master to main python-api-gateway#59
• - python-apigee-connect @parthea docs: migrate links in CONTRIBUTING.rst from master to main python-apigee-connect#33
• - python-appengine-admin @parthea chore: migrate default branch from master to main python-appengine-admin#60
• - python-appengine-logging @parthea chore: migrate default branch from master to main python-appengine-logging#29
• - python-area120-tables @parthea chore: migrate default branch from master to main python-area120-tables#81
• - python-artifact-registry @parthea chore: migrate default branch from master to main python-artifact-registry#67
• - python-asset @parthea chore: migrate default branch from master to main python-asset#274
• - python-assured-workloads @parthea chore: migrate default branch from master to main python-assured-workloads#75
• - python-audit-log @parthea chore: migrate default branch from master to main python-audit-log#28
• - python-automl @parthea chore: migrate default branch from master to main python-automl#234
• - python-bigquery @plamut chore: migrate default branch to main python-bigquery#910
• - python-bigquery-connection @plamut chore: migrate default branch to main python-bigquery-connection#111
• - python-bigquery-datatransfer @plamut chore: migrate default branch from master to main python-bigquery-datatransfer#206
• - python-bigquery-logging @plamut chore: migrate default branch from master to main python-bigquery-logging#28
• - python-bigquery-reservation @plamut chore: migrate default branch from master to main python-bigquery-reservation#153
• - python-bigquery-sqlalchemy @jimfulton chore: migrate default branch from master to main python-bigquery-sqlalchemy#301
• - python-bigquery-storage @plamut chore: migrate default branch to main python-bigquery-storage#283
• - python-bigtable @tseaver chore: migrate default branch to main python-bigtable#411
• - python-billing @parthea chore: migrate default branch from master to main python-billing#107
• - python-billingbudgets @parthea chore: migrate default branch from master to main python-billingbudgets#129
• - python-binary-authorization @parthea chore: migrate default branch from master to main python-binary-authorization#66
• - python-channel @parthea chore: migrate default branch from master to main python-channel#83
• - python-cloud-core @tseaver chore: migrate default branch to main python-cloud-core#136
• - python-cloudbuild @parthea chore: migrate default branch from master to main python-cloudbuild#157
• - python-compute @parthea chore: migrate default branch from master to main python-compute#110
• - python-contact-center-insights @parthea chore: migrate default branch from master to main python-contact-center-insights#31
• - python-container @parthea chore: migrate default branch from master to main python-container#141
• - python-containeranalysis @parthea chore: migrate default branch from master to main python-containeranalysis#173
• - python-crc32c @tseaver chore: migrate default branch to 'main' python-crc32c#80
• - python-data-fusion @dandhlee docs: migrate to main branch python-data-fusion#20
• - python-data-qna @dandhlee chore: migrate to main branch python-data-qna#78
• - python-datacatalog @dandhlee chore: migrate to main branch python-datacatalog#211
• - python-datalabeling @dandhlee chore: migrate to main branch python-datalabeling#138
• - python-dataproc @dandhlee chore: migrate to main branch python-dataproc#248
• - python-dataproc-metastore @dandhlee chore: migrate to main branch python-dataproc-metastore#67
• - python-datastore @dandhlee chore: migrate to main branch python-datastore#217
• - python-datastream @parthea docs: migrate links in CONTRIBUTING.rst from master to main python-datastream#17
• - python-debugger-client @nicain chore: migrate default branch from master to main python-debugger-client#23
• - python-dialogflow @dandhlee chore: migrate to main branch python-dialogflow#372
• - python-dialogflow-cx @dandhlee chore: migrate to main branch python-dialogflow-cx#154
• - python-dlp @dandhlee chore: migrate to main branch python-dlp#239
• - python-dms @dandhlee chore: migrate to main branch python-dms#34
• - python-dns @dandhlee chore: migrate to main branch python-dns#76
• - python-documentai @dandhlee chore: migrate to main branch python-documentai#201
• - python-domains @dandhlee chore: migrate to main branch python-domains#55
• - python-error-reporting @dandhlee chore: migrate to main branch python-error-reporting#165
• - python-essential-contacts @dandhlee chore: migrate to main branch python-essential-contacts#34
• - python-firestore @dandhlee fix: harden lookup of credentials id_token attribute python-firestore#434
• - python-functions @dandhlee chore: migrate to main branch python-functions#102
• - python-game-servers @dandhlee chore: migrate to main branch python-game-servers#178
• - python-gke-connect-gateway @dandhlee chore: migrate to main branch python-gke-connect-gateway#26
• - python-gke-hub @dandhlee chore: migrate to main branch python-gke-hub#68
• - python-grafeas @dandhlee chore: migrate to main branch python-grafeas#98
• - python-iam @dandhlee chore: migrate to main branch python-iam#111
• - python-iam-logging @dandhlee chore: migrate to main branch python-iam-logging#26
• - python-iap @dandhlee chore: migrate to main branch python-iap#19
• - python-iot @dandhlee chore: migrate to main branch python-iot#175
• - python-kms @parthea chore: migrate default branch from master to main python-kms#166
• - python-language @leahecole chore(python): rename default branch to main python-language#188
• - python-life-sciences (good first issue) @dandhlee chore: migrate to main branch python-life-sciences#32
• - python-logging @dandhlee chore: migrate to main branch python-logging#385
• - python-managed-identities @dandhlee chore: migrate to main branch python-managed-identities#65
• - python-media-translation @nicain chore: migrate default branch from master to main python-media-translation#99
• - python-memcache @dandhlee chore: migrate to main branch python-memcache#97
• - python-monitoring @nicain chore: migrate default branch from master to main python-monitoring#206
• - python-monitoring-dashboards @dandhlee chore: migrate to main branch python-monitoring-dashboards#107
• - python-ndb @dandhlee chore: migrate to main branch python-ndb#714
• - python-network-connectivity @dandhlee chore: migrate to main branch python-network-connectivity#74
• - python-network-management (good first issue) @dandhlee chore: migrate to main branch python-network-management#25
• - python-network-security @parthea docs: migrate links in CONTRIBUTING.rst from master to main python-network-security#21
• - python-notebooks @dandhlee chore: migrate to main branch python-notebooks#80
• - python-orchestration-airflow (good first issue) @leahecole chore: Migrate default branch to main python-orchestration-airflow#18
• - python-org-policy @dandhlee chore: migrate to main branch python-org-policy#79
• - python-os-config @dandhlee chore: migrate to main branch python-os-config#113
• - python-oslogin @dandhlee chore: migrate to main branch python-oslogin#111
• - python-phishingprotection @dandhlee chore: migrate to main branch python-phishingprotection#110
• - python-policy-troubleshooter @dandhlee chore: migrate to main branch python-policy-troubleshooter#57
• - python-private-catalog @dandhlee chore: migrate to main branch python-private-catalog#35
• - python-pubsub @plamut chore: migrate default branch to main python-pubsub#479
• - python-pubsublite @dandhlee chore: migrate to main branch python-pubsublite#226
• - python-recaptcha-enterprise @plamut chore: migrate default branch from master to main python-recaptcha-enterprise#114
• - python-recommendations-ai @plamut chore: migrate default branch from master to main python-recommendations-ai#80
• - python-recommender @plamut chore: migrate default branch from master to main python-recommender#122
• - python-redis @plamut chore: migrate default branch to main python-redis#110
• - python-resource-manager @plamut chore: migrate default branch from master to main python-resource-manager#105
• - python-resource-settings @plamut chore: migrate default branch from master to main python-resource-settings#35
• - python-retail @plamut chore: migrate default branch from master to main python-retail#86
• - python-runtimeconfig @plamut chore: migrate default branch from master to main python-runtimeconfig#85
• - python-scheduler @plamut chore: migrate default branch from master to main python-scheduler#126
• - python-secret-manager @plamut chore: migrate default branch from master to main python-secret-manager#187
• - python-security-private-ca @plamut chore: migrate default branch from master to main python-security-private-ca#112
• - python-securitycenter @plamut chore: migrate default branch from master to main python-securitycenter#212
• - python-service-control @parthea
• - python-service-directory @dandhlee chore: migrate to main branch python-service-directory#110
• - python-service-management @dandhlee chore: migrate to main branch python-service-management#51
• - python-service-usage @nicain chore: Migrate default branch to main python-service-usage#34
• - python-source-context @nicain docs: Migrate default branch to main python-source-context#17
• - python-spanner @dandhlee chore: migrate to main branch python-spanner#549
• - python-spanner-django @dandhlee chore: migrate to main branch python-spanner-django#706
• - python-speech @dandhlee chore: migrate to main branch python-speech#242
• - python-storage @dandhlee chore: migrate to main branch python-storage#563
• - python-storage-transfer (good first issue) @dandhlee chore: migrate to main branch python-storage-transfer#13
• - python-talent @dandhlee chore: migrate to main branch python-talent#154
• - python-tasks @dandhlee chore: migrate to main branch python-tasks#157
• - python-test-utils @tseaver chore: migrate default branch to 'main' python-test-utils#52
• - python-texttospeech @dandhlee chore: migrate to main branch python-texttospeech#184
• - python-tpu (good first issue) @dandhlee chore: migrate to main branch python-tpu#36
• - python-trace @dandhlee chore: migrate to main branch python-trace#126
• - python-translate @dandhlee chore: migrate to main branch python-translate#240
• - python-video-transcoder @plamut chore: migrate default branch from master to main python-video-transcoder#88
• - python-videointelligence @plamut chore: migrate default branch from master to main python-videointelligence#206
• - python-vision @plamut chore: migrate default branch from master to main python-vision#220
• - python-vpc-access @parthea
• - python-webrisk @plamut chore: migrate default branch from master to main python-webrisk#118
• - python-websecurityscanner @plamut chore: migrate default branch from master to main python-websecurityscanner#101
• - python-workflows @plamut chore: migrate default branch from master to main python-workflows#89