bernds Thank you so much for the version with 52x52 support !!! a very big request, please add to the new version the ability to play between engines on a 52x52 board !!! some programs have support for large boards, but there is no way to make engine matches! besides that, your program is more convenient and beautiful! thanks!!!

No binaries yet, but if someone wants to test I'd be interested in hearing whether it works well or has some shortcomings. One known issue: I don't know what to do about Ing rules, they aren't listed on the KataGo GTP extensions page.

I guess not much people uses Gentoo linux here, but just in case.

I created a Gentoo overlay which includes a q5Go ebuild (there was none previously), so now everyone should be able to use q5Go with this repository in Gentoo.

during the game of two engines how to stop the game in order to continue later? save, then close? or does it not matter? is it possible to stop for a while? can add a pause button?

There's no reason why you should need KataGo to name the rules for you to use them. KataGo's ruleset is fully documented at https://lightvector.github.io/KataGo/rules.html and every option here is indivdually toggleable, so if you want to support any new rules, you can find the closest combination of rules there and use that - and if there isn't a practically-exact match, you can ask other people specialized in rules beasts and corner cases for help in figuring what would be the closest match.

I do, actually...
Neat. You might want to add a "doc" USE flag which requires pandoc as a build dependency. The README will get installed if that program is present.

You probably also need a few additional dependencies beyond qtgui, such as qtsvg and qtmultimedia.

in the sidebar during analysis (primary move:), some coordinates are displayed incorrectly. e.g. (af19) - ('19), (ad19) - (^19)