New #libxml2 version 2.9.12 breaks validation with some incorrect DTDs, such as old #XHTML 1.0 DTDs: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=993638#50 — Are there other users likely to be affected when they upgrade to this version?
Suivre
I've eventually found that the was due to a #Debian specific bug introduced in 2012 in the w3c-dtd-xhtml package (apparently to shared some files between the XHTML 1.0 and XHTML 1.1 DTDs). Details: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=993638#102
