Agree! I was thinking also of in house support code, tooling, infrastructure maintenance, local IT stuff, build tools. Stuff that runs in-house, might be important but if it breaks, there won't be a 2am call from Australia or a public tweet about how "Product <X> from company <Y> just lost me all my data".
I have seen in-house bug tracking database backups fail and I have seen upset customers that spread the word to other potential customers. I'll take an in-house database backup failure any day.
This is for a small niche industry where everyone knows everyone a bad word or hit can mean the end of the company.
git rm <code that customer will never run>