Thanks for your reply, Sarah. I'm sorry, what's not clear?

I want cxs to scan more than one specific file in a single execution. For example, let's say I want to scan three files:
index.php
whatever.php
somefile.suspicious
If I specify all three files on the command line:
cxs index.php whatever.php somefile.suspicious
cxs only scans the first file and ignores the rest, which is understandable, it says so in the syntax: "cxs [OPTION]... RESOURCE" <-- (single resource)
Ok, so if I create a file called list_of_files with the following content:
file:index.php
file:whatever.php
file:somefile.suspicious
... and use the "--xtra list_of_files" option (cxs' help says "--xtra [file] points to a file containing a list of regular expression matches and filenames that cxs will additionally scan for"), cxs won't run unless I specify at least one resource (ignoring the obvious list of files mentioned in --xtra), and when I do specify a resource, it only scans that resource, ignoring the list of files altogether. Does --xtra even work? Am I using it right?
I'll gladly submit a ticket if we can be sure there's absolutely no way to scan multiple specific files in a single run. I wouldn't want to bother the dev team otherwise.