SUMMARY
The firewalld widget (from Thomas Woerner <twoerner@redhat.com>, Jiri Popelka <jpopelka@redhat.com> and Eric Garver <e@erig.me>) displays a tooltip (the one when you move the mouse point over it, not clicking) with unformatted HTML code
I mean: "<fontzise="3"><nobr>...</font>"

STEPS TO REPRODUCE
1. Add the firewall widget to the taskbar
2. Move the mouse pointer over it
3. ckeck the unformatted HTML code displayed

OBSERVED RESULT
"<fontzise="3"><nobr>...</font>"

EXPECTED RESULT
A well formatted output

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20201023
KDE Plasma Version: 5.20.1
KDE Frameworks Version: 5.75.0
Qt Version: 5.15.1
Kernel Version: 5.8.15-1-default
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-3770 CPU @ 3.40GHz
Memory: 14.6 GiB of RAM
Graphics Processor: GeForce GTX 970/PCIe/SSE2
ADDITIONAL INFORMATION

This is a old bug, present since 5.18 at least. Amazing it is still there.