is one of the enhancements listed under "Miscellaneous Enhancements", the description stating:
"Visual FoxPro includes more details and help for certain error messages.".

Using an admittedly error-prone technique I eyeball-compared the error messages by number lists in VFP7SP1 with VFP8 beta.

The comparison started out auspiciously - message # 1 has been changed from "File does not exist" to "File "name" does not exist".

Thereafter, however, I was unable to find a single other message that included 'more details'.

I found that #1161 - "too many...in demo version." - has been dropped in VFP8 beta.

I found that #1980 - "Ignore" - has been added in VFP8.

I found that #1990 - "Cancel" - has been added in VFP8.

I found that #2053 was out of (sequential) order in the VFP8 list.

I found that message numbers 2056 - 2091 (some numbers skipped) have been added in VFP8. These relate to new features of the version.

I suppose that "more details and help" may well have been added to the specific Help entry for an error. My interpretation of the Wish List entries requesting improved error messages was to include more helpful information in the error messages themselves. For instance, "Source code not found" (an unnumbered message) should say "Source code < for xxxxxxxx > not found". There are numerous messages that need enhanced detail in the message itself.

Finally, the (new) message #2091 states: "Table "name" has become corrupted. The table will need to be repaired before using again." and its related Help detail states: "Visual FoxPro has detected that the record count in the table header does not match the calculated table size. You can repair the table by using an appropriate third-party Visual FoxPro table repair utility.".
Firstly, I believe that stating that the table has become "corrupted" is a bit strong and hardly indicative of the actual problem. Something along the lines of: "Table "name" has a discrepancy between the header record count and the number of physical records. Repair necessary." would be much more accurate.
Secondly, I don't think that requiring use of a third party utility is appropriate, especially when a few people here (on UT) have devised working all-VFP routines to do the repair. It would be much more in keeping with VFP's history to provide the 'tool' to do this specific repair in the product.

I realize that the documentation too is in beta status.
At this point I recommend that Wish List entries requesting improved error message details REMAIN in the Wish List.