I had an incorrect fix for issue2550601. Changed schema to define class patches not patch. Changed commented out patches section in bug.item.html to use patches-1 an not patch-1 as a result of schema changes. The show open Milestones link had a leak of the @group value. If you clicked on show open tasks or show open bugs they group by priority. The url being formed for show open milestones was inheriting the @group if you were on an index page for bugs or milestones. Explicit set the @group to status (which a milestone does have) prevents the @group=priority from being applied to a milestone index page which results in a red error banner stating priority is an invalid param for milestones. ./demo.py -t devel now runs without obvious breakage.

try:
    # Python 3+
    from http import cookies as Cookie
    from http.cookies import CookieError, BaseCookie, SimpleCookie
    from http.cookies import _getdate as get_cookie_date
except:
    # Python 2.5-2.7
    from Cookie import CookieError, BaseCookie, SimpleCookie
    from Cookie import _getdate as get_cookie_date