Bug#1010134: xml-core: please improve message "error: entity not registered" with details

Package: xml-core
Version: 0.18+nmu1
Severity: wishlist

When testing the patch for bug 1003933, I get the following error
messages:

update-xmlcatalog: error: entity not registered
update-xmlcatalog: error: entity not registered
update-xmlcatalog: error: entity not registered
update-xmlcatalog: error: entity not registered

They should be more detailed, e.g. telling which entity is not
registered.

-- System Information:
Debian Release: bookworm/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'stable-updates'), (500, 'stable-security'), (500, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 5.17.0-1-amd64 (SMP w/8 CPU threads; PREEMPT)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=POSIX, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages xml-core depends on:
ii  sed        4.8-1
ii  sgml-base  1.30

xml-core recommends no packages.

Versions of packages xml-core suggests:
ii  debhelper  13.7.1

-- no debconf information