[Trac] Css expiration

[Emmanuel Blot]

I just upgraded our Trac system today with the latest release from the 
main branch. CSS and ClearSilver templates have changed since the last 
upgrade, but it seems that the browser (FireFox) does not detect that 
CSS files have changed. Therefore, some styles are lost in the new 
pages, as Firefox keeps using the old CSS files instead of retrieving 
the fresh ones.

One solution is to force a refresh of the page in trouble (F5), but it 
is not that easy to tell every single user in the team that if he/she 
thinks there's a problem on a Trac page, he/she should manually refresh 
the page. Closing/Re-opening the browser does not help.

Coud Trac return an expiration header info to the browser, to force the 
browser to refresh its cache, or something similar ?

Thanks,
Emmanuel