"Tools - Extension Manager... - Add... - File type:" contains  "All files (*.*)"
and "Extension", but also many entries for extension sub-components
("Configuration Data", "Configuration Schema", "UNO Dynamic Library Component",
etc.).

While it is technically correct that such extension sub-components can be
treated as full-blown extensions of their own and can be installed on their own,
this is probably too geeky a feature to support it with individual entries in
the filter list.  (Even without those filter list entries, it would still be
possible to actually install such extensions, just not pick them so "easily"
from the dialog.)

The fix for issue 114962 introduces a new kind of extension sub-component
(*.components XML files, containing passive registration information about
accompanying UNO component files), and thus adds a new entry to the filter list
("UNO Components").  However, it does not make much sense to install individual
*.components files as full-blown extensions (they need the accompanying UNO
component files to work properly, so only make sense within an .oxt container).

Instead of adding special code to remove just the "UNO Components" filter list
entry, it is probably better to remove all the filter list entries for all the
extension sub-components, leaving just "All files (*.*)" and "Extension".