I've come across this picture numerous times, and it's featured in the
Tactica Imperialis in the section on the Lyubov Campaign. I have no idea which regiment it is, and I haven't been able to find out from other sources:
Any tips? It may be any of the infantry regiments mentioned in the book:
Edit: Did some digging - looks like they're the 122nd Cadian. And they were featured in the 3rd e. Codex Cityfight in a scenario against Night Lords.