What is the meaning of < > in language specifications?

Question

When reading how to use certain commands I've come upon items that are wrapped in < >. I understand brackets denote optional but what is the meaning of these <>.

'git pull' [options] [<repository> [<refspec>...]]

Answer 1

Here, <> just denote named placeholders - these are helpful if e.g. more than one argument is optional or a name contains a space.

It is based on the Backus–Naur Form (BNF), thanks to @etuardu for pointing this out!