core Git. Porcelains expose more of a <<def_SCM,SCM>>
interface than the <<def_plumbing,plumbing>>.
+[[def_per_worktree_ref]]per-worktree ref::
+ Refs that are per-<<def_working_tree,worktree>>, rather than
+ global. This is presently only <<def_HEAD,HEAD>>, but might
+ later include other unusual refs.
+
+[[def_pseudoref]]pseudoref::
+ Pseudorefs are a class of files under `$GIT_DIR` which behave
+ like refs for the purposes of rev-parse, but which are treated
+ specially by git. Pseudorefs both have names that are all-caps,
+ and always start with a line consisting of a
+ <<def_SHA1,SHA-1>> followed by whitespace. So, HEAD is not a
+ pseudoref, because it is sometimes a symbolic ref. They might
+ optionally contain some additional data. `MERGE_HEAD` and
+ `CHERRY_PICK_HEAD` are examples. Unlike
+ <<def_per_worktree_ref,per-worktree refs>>, these files cannot
+ be symbolic refs, and never have reflogs. They also cannot be
+ updated through the normal ref update machinery. Instead,
+ they are updated by directly writing to the files. However,
+ they can be read as if they were refs, so `git rev-parse
+ MERGE_HEAD` will work.
+
[[def_pull]]pull::
Pulling a <<def_branch,branch>> means to <<def_fetch,fetch>> it and
<<def_merge,merge>> it. See also linkgit:git-pull[1].