For git version 2.23 and above:
To enable the ignorance for one command,
git blame --ignore-revs-file=.git-blame-ignore-revs <other options>
To set this permanently for blender,
git config blame.ignoreRevsFile .git-blame-ignore-revs
To disable the ignorance for one command,
git blame --ignore-revs-file="" <other options>
Effect of this option considering rB3e101759b1b726e3cc16c69b2619cd1d82b00a8e
$ git blame build_files/cmake/Modules/FindOpenColorIO.cmake -L 72,+3 b93da9b01e16 (Sergey Sharybin 2012-09-15 10:03:17 +0000 72) SET(OPENCOLORIO_INCLUDE_DIRS ${OPENCOLORIO_INCLUDE_DIR}) 3e101759b1b7 (Campbell Barton 2020-10-05 16:02:32 +1100 73) ENDIF() b93da9b01e16 (Sergey Sharybin 2012-09-15 10:03:17 +0000 74) $ git blame --ignore-revs-file=.git-blame-ignore-revs build_files/cmake/Modules/FindOpenColorIO.cmake -L 72,+3 b93da9b01e16 (Sergey Sharybin 2012-09-15 10:03:17 +0000 72) SET(OPENCOLORIO_INCLUDE_DIRS ${OPENCOLORIO_INCLUDE_DIR}) b93da9b01e16 (Sergey Sharybin 2012-09-15 10:03:17 +0000 73) ENDIF() b93da9b01e16 (Sergey Sharybin 2012-09-15 10:03:17 +0000 74)
https://git-scm.com/docs/git-blame#Documentation/git-blame.txt---ignore-revs-fileltfilegt
https://git-scm.com/docs/git-config#Documentation/git-config.txt-blameignoreRevsFile