in mozdownload/scraper.py [0:0]
def thunderbird_latest_version_filter(x):
"""Ignore Thunderbird versions that mozilla-version does not accept as valid.
mozilla-version is only used to find the "latest" versions; these are old
and will not be relevant.
"""
accepted_invalid_versions = ("0.7rc", "1.0rc", "2.0.0.0", "2.0.0.0rc1", "10.0-real")
return x not in accepted_invalid_versions and \
re.match(RELEASE_AND_CANDIDATE_LATEST_VERSIONS['latest'], x)