This directory contains Trac's default Genshi templates.

It is not advised to make local modifications to those files after
installation, as they might be lost during the installation of a new
Trac version.

As an alternative, you can copy the templates you want to modify and
place them in the templates/ directory of your Trac environment or in
the location specified in the trac.ini file under the `[inherit]
templates_dir` setting (the former having precedence over the latter).

Nevertheless, if you use such a locally modified template, it will be
easy to miss the functionality provided by a newer version of the
template, after an upgrade. Because of that, the preferred way to
alter the output would be to write plugins doing Genshi stream
transformation (see for example the sample-plugins/ticket_clone.py),
as this is robust when upgrading to a newer version of Trac: you only
have to check that your filtering still matches and that the
transformation works as expected...
