Managing distributed version control at scale is one of the core challenges facing nearly every growing software company. Performance issues, the increasing incidence of merge conflicts, preemptive CI, build system integration... this is definitely a topic you can go deeply into, and make an impact at many companies.

On the flip side, you are now a source control/build system engineer, and it's pretty easy to get typecast as such (given the outsize impact your specialist skillset will have).