[KevinH]

I searched the sigil_bs4 code for use of set_trace and it does *not* appear to be used anyplace inside our sigil_bs4 according to a github search. It is probably a hold over from an earlier version of bs4.

We could try commenting this line out of sigil_bs4 files: dammit.py, element.py, and builder/_html5lib.py

from pdb import set_trace

And according to a search pdb is the python debugger module so it is probably a leftover from an old debugging session.

I think we can safely remove it from all 3 files.

What I do not understand is why this error never showed up before. Was pdb changed in Python 3.14.2?