why 'merging'?

[Neal Becker]

 hg pull ssh://nbecker6/xxx
pulling from ssh://nbecker6/xxx
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
(run 'hg update' to get a working copy)

hg update
merging test/test_ldpc_pipelined.py
0 files updated, 1 files merged, 0 files removed, 0 files unresolved

The use of the word 'merge' confused me.  After the so-called merge, I find 
that the remote file and the local file are binary-equal.