setBfree gui not showing, solved, but why

Insofar it was quite a bit of back and forth, it isn’t easy for me to tell it in a structured way.
First things first; this is on Slackware Current with most audio things installed either from slackbuilds.org or from slackware.uk.
Soundserver is jack, started and configured with cadence.
Ardour is official version 9.7

I found these two forum threads:

1)I installed setBfree from slackbuilds, and it didn’t include setBfreeUI, i don’t think i even tried it as a plugin in Ardour.
2) I then downloaded setBfree from x42-plugins and installed it with the included script.
That did give me setBfreeUI as standalone, but it wasn’t shown as a plugin in ardour at all (i scanned and all, not sure if for lv2 that is even needed).
3) I then downloaded the setBfree deb-file from kx.studio.com, converted it with deb2tgz and installed it (systemwide), and to my surprise it worked fine as a plugin in ardour.

I don’t really understand compiling, linking, libraries, plugins, but simply use them.
Not understanding too much, at least i compared setBfree form x42-website and from kx.studio, and i think they do differ

ROOT_Slack# diff /home/user/Downloads/setBfree/b_synth.lv2/ /usr/lib/lv2/b_synth/ -r
Binary files /home/user/Downloads/setBfree/b_synth.lv2/b_synth.so and /usr/lib/lv2/b_synth/b_synth.so differ
diff -r /home/user/Downloads/setBfree/b_synth.lv2/b_synth.ttl /usr/lib/lv2/b_synth/b_synth.ttl
29c29
<       lv2:microVersion 0 ;lv2:minorVersion 2078 ;
---
>       lv2:microVersion 0 ;lv2:minorVersion 2070 ;
Binary files /home/user/Downloads/setBfree/b_synth.lv2/b_synthUI.so and /usr/lib/lv2/b_synth/b_synthUI.so
differ
Only in /home/user/Downloads/setBfree/b_synth.lv2/: modgui.ttl
ROOT_Slack#

I’d like to know how to troubleshoot such problems in other cases too, in general, even though setBfree now works for me. I don’t have such problem often, but sometimes, and usually i then just give up. Starting Ardour from command-line or having a look at the info-box in ardour didn’t really help.
Thanks in advance.

That is unusual. The install script does not even install the JACK app, it only deploys the LV2 plugin.

A common issue with the GUI not showing are missing openGL libraries. e.g. libmesa or libgl are not available on the target system.

As for the plugin not being found. lv2ls would be the first step to investigate. That lists all LV2 plugins on the system.

Yeah, as said, it was quite a wild ride, and i might confuse a few things. I think i copied setBfreeUI after i unpacked the tar.gz file to /usr/local/bin; myself. Sorry i was unclear about that part.

I thought i might miss a library (thanks for the ones to look into, libmesa and libgl), hence my astonishment that the kx.studio version just worked.

lv2ls: thanks. I didn’t know it.

So i uninstalled the kx.studio version and re-installed the x42-plugins version. It is to be found at
~/.lv2/b_synth.lv2/
but lv2ls doesn’t list it.

user$ lv2ls | grep b_synth
user$ lv2ls | grep setB
user$

If i copy
~/.lv2/b_synth.lv2 /usr/lib64/lv2
setBfree is available as a plugin in ardour.

user$ ls -ahl ~ | grep lv2
drwxr-xr-x 15 user users 4.0K Jun 9 21:32 .lv2
user$ ls -ahl ~/.lv2/ | grep b_synth
drwxr-xr-x 2 user users 4.0K May 5 03:45 b_synth.lv2