It appears that since r45973, there is an enhancement to MediaWiki that
allows the software to follow double redirects, and conceivably triple- and
higher-level redirects, up to a configurable limit ($wgMaxRedirects). This
raises a few questions:
1) Should [[Special:DoubleRedirects]] be changed to show only those
redirect chains that exceed $wgMaxRedirects in length, since those are the
only ones that really need fixing under the current software?
2) If not, should there be a new Special: page to list such "excessive"
redirect chains?
3) How can the users (not sysadmins) of a given wiki determine what the
value of $wgMaxRedirects is for their wiki? In particular, what value is
being used currently on enwiki and other WMF projects?
4) Shouldn't this configuration change have been announced to the user
community of each project so that they could consider how it affects their
internal policies on what types of redirects to allow?
Russ