Where is the Textools menu? This seems like a ridiculous question but i installed this addon called Textools by renderhjs
http://renderhjs.net/textools/blender/
I installed it(ver 2.90.1) and absolutely cannot find the tool on the interface in the UV editing workspace or the standard 3d viewport. Is this due to conflicts with the version? I definitely searched the interface for it.
If you press N in the 3D viewport, a tool menu pops up in the top right corner. This menu has categories, separated by tabs running vertically on the side. Have a look and see if it added anything here (look in both edit mode and object mode):

I am basing this off the image that appears on the add-on's website - you can see all the &quot;action&quot; seems to happen from the same menu. The site says it has support for 2.8, but if it's not there, perhaps it isn't ready for 2.9 yet.