This is a suggestion for chromium developers that I've implemented locally for myself and decided to share the idea which could benefit other developers if adopted officially.

* chromium's bisect-builds.py [1] is used to bisect bugs/regressions.

* quite often the download phase is VERY slow due to increased load on googleapis.com servers thus it takes a few minutes instead of a few seconds to download a revision.

* hence the improvement: bisect-builds.py could use 7zip-packed mini-installer.exe from the snapshot directory [2] to download 2.5-3 times less data: ~40MB instead of 100-120MB.

My local implementation simply invokes 7z two times:

	class PathContext(object):
	  def __init__(self, base_url, platform, good_revision, bad_revision,
	    #............................................
	    elif self.platform in ('win', 'win64'):
	      self.archive_name = 'mini_installer.exe'
	      self._archive_extract_dir = 'Chrome-bin'

	#...........................................

	def UnzipFilenameToDir(filename, directory):
	  #...........................................
	  os.system('7z x "{0}" "-o{1}" 1>nul'.format(filename, directory) +
	         ' & 7z x Chrome.7z 1>nul' +
	         ' & del Chrome.7z')

A proper implementation should check whether 7z.exe is available, of course.

[1]: https://chromium.googlesource.com/chromium/src/+/master/tools/bisect-builds.py
[2]: https://commondatastorage.googleapis.com/chromium-browser-snapshots/index.html?prefix=Win_x64/435372/