I\'m configuring PostgreSQL db for the Bitbucket Server on Windows. In the official guide it says that:
The database must be configured to use the UTF-8 c
There is no UTF8 collation. UTF8 is a way to encode characters as numbers, a so-called encoding. Collations define how characters (and composites) are ordered.
While you have to pick a collation that matches the database encoding with PostgreSQL on UNIX, that is not required on Windows. Maybe the documentation you are reading is targeted at UNIX.
You should ask the people who wrote the software to tell you what collation to use.