The package was added for #4550 (making Osmocom packages build on CentOS 8), specifically it is an indirect dependency of osmo-pcap that was not available on CentOS 8.
From osmo-ci.git, scripts/osmocom-obs-link.sh:
# osmo-pcap: depends on libzmq
osc linkpac openSUSE:Factory zeromq "$PROJ"
osc linkpac openSUSE:Factory libunwind "$PROJ"
osc linkpac openSUSE:Factory libsodium "$PROJ"
osc linkpac openSUSE:Factory openpgm "$PROJ"
The package had built fine initially, and so the binary package was available. However, as it is a link to the openSUSE:Factory package with a diff (some modifications were needed to make the openSUSE package build on CentOS), the package showed up as "broken" after the openSUSE package got modified and the diff did not apply anymore.
The modifications in the openSUSE package are not relevant for us, it uses the same sources but patches some python script to run with python3:
https://build.opensuse.org/package/rdiff/openSUSE:Factory/openpgm?linkrev=base&rev=10
I couldn't find a command to "rebase" the diff with osc without spending much time, so I just hardcoded to the previous revision (9) for now:
$ osc setlinkrev -r 9
The package rebuilt and shows up as "successful" now.
If we should need to upgrade the package to a newer version, it's probably easiest to remove the link and use it as normal package; dealing with the link + diff is quite confusing for somebody who only uses osc occasionally. (On a side note, it appears that upstream for this package is dead anyway.)
EDIT: for future reference, apparently "osc pull" should be used inside the directory to rebase the patch, saw a message scrolling by that claims this.
