Larry Page asking how to change User Agent in Java
twitter.com
twitter.com
also these- but I'm pretty sure there have been others - maybe someone will find them:
Q: Setting User-Agent Field? - https://news.ycombinator.com/item?id=14250473 - May 2017 (1 comment)
Q: Setting User-Agent Field? - https://news.ycombinator.com/item?id=1655648 - Sept 2010 (5 comments)
An essay on why Java is harmful.
A link to some RFC draft that states user agents shouldn’t be changed.
A solution on how to change a user agent in another language/framework
A Mod closes the question as duplicate while linking to how change the UA in PHP.