@Marcus: yup, that seems to be it:

jani@saegusa:~$ dpkg -l ’libcpd*’ ’cpdb*’
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Nimi Versio Arkkitehtuuri Kuvaus
+++-========================-=================-=================-======================================================
ii cpdb-backend-gcp 1.0.0-0ubuntu2 amd64 Common Print Dialog Backends – Google Cloud Print Back
ii libcpdb-libs-common0:amd 1.1.1-0ubuntu1 amd64 Common Print Dialog Backends – Interface Library for B
jani@saegusa:~$ SAL_DISABLE_CPD=true libreoffice –norestore
func=xmlSecCheckVersionExt:file=xmlsec.c:line=188:obj=unknown:subj=unknown:error=19:invalid version:mode=abi compatible;expected minor version=2;real minor version=2;expected subminor version=25;real subminor version=26

That is, no stack trace nor other apparent problems when starting LO with SAL_DISABLE_CPD=true.