quote from the current README file:
The upper and lower bounds are not explicit, as they are subject to change over time.

quote from the current index.bs file (official spec):
NOTE: While implementations may choose different values, the recommended upper bound is 8GiB and the recommended lower bound is 0.25GiB (or 256MiB).

It appears to me the original consensus is that the spec doesn't specify concrete bound values but let the implementations to decide and the values can be adjusted over time.

However, the documents also recommend explicit values that inevitably would become dated and causes confusing.

This PR removes the explicit values and emphasizes that the implementations can adjust the bound values. It makes it clear that adjusting the bounds to values different from the old recommend values is not a violation of the spec.

@guohuideng2024 as discussed can we add an explicit mention that implementors may also choose different max/min boundaries per device? Then we're good to merge!

@guohuideng2024 as discussed can we add an explicit mention that implementors may also choose different max/min boundaries per device? Then we're good to merge!

Now the text mentions the boundaries can differ on different device types without mentioning "geographic regions".