@Vlad
I don't have a non beta version of FBReader installed anywhere.
I'm using Lighttpd 1.4.31 as my webserver on debian.
original output
Code:
<link href="feed.php?page=1&db=0" type="application/atom+xml;profile=opds-catalog;kind=navigation"/>
with my change
Code:
<link href="/cops/feed.php?page=1&db=0" type="application/atom+xml;profile=opds-catalog;kind=navigation"/>
But the weird thing is, I changed the code back to original and OPDS kept working fine on my phone and tablet.
So I don't know if there was some kind of caching problem or what.
I'll have to test again when I'm not on my home wi-fi.