On a Testing (Forky) with Cinnamon, after installing:
< chromium chromium-l10n chromium-driver webext-ublock-origin-chromium >
at Chromiun start I receive:

===========================================================================
Unable to load extension from:
/usr/share/chromium/extensions/ublock-origin. The extension cannot be
installed because it uses an unsupported manifest version.
===========================================================================

Impossible to apply some directives in chrome://flags, because it
doesn't exists more the voice "Allow legacy extension manifest version"

PS
The same, despite the slightly different version of this extension, in
Stable (Trixie, in my case with kde)

Hello,

Am Samstag, dem 13.12.2025 um 13:24 +0100 schrieb Mauro Sacchetto:

This is a know issue. Please see

https://bugs.debian.org/1102005

for further information. The Chromium version of ublock-origin is discontinued
and will eventually be removed from Debian or replaced by ubo-lite. Currently
it is still usable but you have to use a workaround to re-enable the extension
in Chromium again. In #1102005 you will find more information how to achieve
that.

Regards,

Markus