Understanding and handling a "groff-message 734" failure

[c.buhtz@posteo.jp]

Hello,

I'm an upstream maintainer and someone who do support the packaging 
process on the site of Debian pointed me [1] to an lintian message.

    {
      "type": "failure",
      "message": "groff-message 734: bad argument name 'P' 
[usr/share/man/man1/backintime-config.1.gz:1]"
    }

The related upstream source file must be this [2]. Using the search 
machine of my trust it seems that errors like this are often false 
positive. But I lack some basic knowledge about linitian work. That is 
why I ask.

Based on the file the message points to it seems to be related to 
manpage generation, right?

What is "groff-message"? Is this a commandline tool linitian used to 
check manpage files for errors? I couldn't find it. I thought it would 
be a good idea to look into its documentation and to run that test 
myself to better understand it.

The line 734 [3] looks OK for me. Don't know what is wrong there. I'm 
also not sure if the error points to line 734 in the unpacked file or 
into the package gz-archive.

Just ignoring isn't an option for me.

Thanks for help.
Christian

[1] -- <https://salsa.debian.org/jmw/pkg-backintime/-/merge_requests/6>
[2] -- 
<https://github.com/bit-team/backintime/blob/master/common/man/C/backintime-config.1>
[3] -- 
<https://github.com/bit-team/backintime/blob/979b757d2cbbe65b332c5fd15244d400a9d80983/common/man/C/backintime-config.1#L734>