It seems so:

$ hg log -b pip
changeset:   5023:5e2888db6c48
branch:      pip
user:        anatoly techtonik <techtonik@gmail.com>
date:        Mon Jan 11 14:43:20 2016 +0300
summary:     build_scripts: self.announce --> log.info because it is visible

changeset:   5022:9250620c7219
branch:      pip
user:        anatoly techtonik <techtonik@gmail.com>
date:        Mon Jan 11 01:28:45 2016 +0300
summary:     build_scripts: Fix long term bug with setting
self.target_platform

changeset:   5021:70dde3937c9b
branch:      pip
user:        anatoly techtonik <techtonik@gmail.com>
date:        Mon Jan 11 01:20:29 2016 +0300
summary:     setup.py: Remove legacy support code for Python<2.3

changeset:   5020:a4d7e495f2f6
branch:      pip
user:        anatoly techtonik <techtonik@gmail.com>
date:        Sat Jan 09 20:44:56 2016 +0300
summary:     Rollback cdfb1a3 - support "pip install --editable ."
(issue2550866)


The branch was merged. That's the reason you see "(inactive)", which just
means that all heads of the branch are part of other branches, i.e. there is
no unmerged development in them:

$ hg log -r 'children("pip")'
changeset:   5024:edf62f78605f
parent:      5019:9bb20454f409
parent:      5023:5e2888db6c48
user:        anatoly techtonik <techtonik@gmail.com>
date:        Mon Jan 11 17:43:37 2016 +0300
summary:     Merging reverted "pip develop" compatibility into default


If this bothers you, you could explicitly close the branch using:
hg commit --close-branch