[tz] "non-standard" timezones

[Shawn Steele]

Hoping someone can provide examples or something. 

Are there cases where people are using their own Timezone data?  (I'm thinking like a company or research station or something that doesn't snap to some "normal" tz for some reason)  Any examples?  For non-standard timezones is there a recommendation for naming conventions?  (Eg: etc/mine ?)

In several systems it's possible to adjust the Timezone data, and, of course someone could edit and install their own versions of the tzdb data on systems that consume it, but I'm curious if it ever happens in practice?

Thanks,
Shawn