The property rvparse to the Action API prop=revisions has been deprecated since MediaWiki 1.30 in 2017. Clients should use action=parse to parse a page's wikitext to HTML when necessary.
Discussion on T241208 is considering removing rvparse to improve site stability and performance. You may want to convert to action=parse now rather than waiting to see if the decision is made to actually remove rvparse.
There are multiple problems with this, it's burried in very old code that I wrote so long time ago I am not sure about the logic anymore. This commit removes it - https://github.com/huggle/huggle3-qt-lx/commit/8638b179899ff92b2a3ef2defcb6d17de511a791 but it needs some intensive testing, because I literally just removed the rvparse from API call and now I am observing what it broke.
The weird part is, that I can't see that anything is broken - why did we even use this rvparse thing in a first place?
BTW I can already see another deprecation warning for some other API call, you deprecate these API calls in a light speed... Even that action=parse is already full of deprecated options, I think you should think things through before release ;)
I mean, try to get some inspiration from UNIX, it was invented around 1970 and most of old C code from that time still compile on modern UNIXes... that's what I call a stable API :P
ok I couldn't find any issue after I removed it, I believe it's resolved now, this version with fix was not released yet, and even when it is, old versions of Huggle will still be used for a while though.