Question How to translate the tooltip texts of the bbcode editor buttons?

Ok, then try followings: Rename the english libraries.ini and templates.ini. You find these in "administrator/components/kunena/language/en-GB" and "components/kunena/language/en-Gb".
So you can see, if it's the cache or another language file were you get this translation.

Thanks for your support, I really appreciate it.

I renamed the files in 3 locations:
1. your #1 location
2. your #2 location
3. administrator/language/en-GB/en-GB.com_kunena.libraries.ini

(offtopic: I don't understand why there are two "en-GB.com_kunena.libraries.ini" files - one in administrator/components/kunena/language/en-GB and another in administrator/language/en-GB)

I cleared browser cache. I even rebuilt the plugins...

It still shows the tooltips in English. Hence, this should be a cache issue?

The following cache has been disabled since the beginning:
1) Joomla main cache (conservative)
2) all cache plugins
3) no server cache (nginX) is used
4) Kunena internal caching is disabled
5) CDN is disabled

I'm out of ideas

I don't understand why there are two "en-GB.com_kunena.libraries.ini" files - one in administrator/components/kunena/language/en-GB and another in administrator/language/en-GB)

Yes, that's a redundant and will removed (it's on our list).

It still shows the tooltips in English. Hence, this should be a cache issue?

Could be a cache problem, or your Kunena template has own language files.

Hi,

I switched to Crypsis and the issue remains.

If its a cache issue... might there be some cache that I don't know about yet?

Yes, there are more than one cache. On Joomla template it's a own cache possible, browser cache is very stubborn, or media/kunena/cache etc.. I also not known all possibility.

Same problem with our forum. Cleared all cache (Kunena and Joomla) and browser cache. Language for bbcode editor buttons is still English.