It took slightly longer than expected for me to track down an explanation of their business model. I think it boils down to "run cheap until we have one".
https://developers.revolt.chat/faq/monetisation
Dunno if this is the case here, but there are use cases for manual timestamps, for example when you want to differentiate between metadata updates / formatting changes and content updates/reviews.
Ah yeah, that's true, last commit to that file was actually on Apr 19th 2022.. https://github.com/revoltchat/documentation/commits/master/d... Too bad the metadata isn't surfaced somewhere so you could kinda discern "last substantial change" vs. "last actual time anyone made an edit of any sort to this file".