Larry the other thing it does is when run for existing company data, it updates the physical tables to match the dictionary. In case you're asking about this in reference to your post about the SQL database being restored that didn't contain the UDF columns, first know it's a Premium bug which @JohnnyPabian reported awhile back with UDF Maintenance / Update where after updating a certain number of company codes it just stops updating. So doing the o'Activate(""A/R"", ""ABC"") would in fact physically add back the missing UDF columns to the A/R tables (b/c it's defined in the dictionary).
In the 4.early days it would also restore what was known as ""embedded IO"". E.g. back in the day there was a both a CI_Item and IM1 and sometimes you wouldn't see the item description in S/O Entry and stupid things like that. This 2-liner from Syzcon to place back the embedded IO was the fix. I have a lot of bar room arcane knowledge on embedded IO scheme, why it got invented, who put it out of its misery, and other MAS90 trivia.
Besides that, this has been used to fix a variety of strange dict issues where data is not saved or a lookup doesn't behave like these:
https://90minds-com.socialcast.com/messages/27661218
https://90minds-com.socialcast.com/messages/25809221
https://90minds-com.socialcast.com/messages/25069781