[xubuntu-users] missing file

[hans Schneidhofer]

hi list,
synaptic  tells me, that there is a missing file during an
installation.

The file »
http://ppa.launchpad.net/oibaf/graphics-drivers/ubuntu/pool/main/m/mesa/libosmesa6_19.2~git1905111930.974c4d~oibaf~b_amd64.deb«
 could not be downloaded.

First question:
how can I find out, which file or program calls this missing file ?

2nd question:
was looking on hithub, but there is no such file
libosmesa6_19.2~git1905111930.974c4d~oibaf~b_amd64.deb

Maybe, this is a typo ? So it would be good to know, which file or
program is calling this file, so I have a chance to look, if there is a
typo in a calling library ???

Thanks a lot for helping here

bye hans