+* improve performance and avoid head-of-line blocking on slow storage
+ (done for most git blob retrievals, Xapian needs work)
+
+* allow optional use of separate Xapian worker process to implement
+ timeouts and avoid head-of-line blocking problems. Consider
+ just-ahead-of-time builds to take advantage of custom date parsers
+ (approxidate) and other features not available to Perl bindings.
+
+* integrate git approxidate parsing into Xapian w/o spawning git
+
+* HTTP(S) search API (likely JMAP, but GraphQL could be an option)
+ It should support git-specific prefixes (dfpre:, dfpost:, dfn:, etc)
+ as extensions. If JMAP, it should have HTTP(S) analogues to
+ various IMAP extensions.
+
+* scalability to tens/hundreds of thousands of inboxes
+
+ - inotify-based manifest.js.gz updates
+
+ ...
+
+* lei - see %CMD in lib/PublicInbox/LEI.pm
+ (there's a truckload here..)
+
+* make "git cat-file --batch" detect unlinked packfiles so we don't
+ have to restart processes (very long-term)
+
+* linter to check validity of config file
+
+* linter option and WWW endpoint to graph relationships and flows
+ between inboxes, addresses, Maildirs, coderepos, newsgroups,
+ IMAP mailboxes, etc...
+
+* pygments support - via Python script similar to `git cat-file --batch'
+ to avoid startup penalty. pygments.rb (Ruby) can be inspiration, too.
+
+* highlighting + linkification for "git format-patch --interdiff" output
+
+* highlighting for "git format-patch --range-diff" output
+ (linkification is too expensive, as it requires mirroring)
+
+* support UUCP addresses for legacy archives
+
+* support pipelining as an IMAP/NNTP client for -watch + lei
+
+* expose lei contents via read/write IMAP/JMAP server for personal use
+
+* git SHA-256 migration/coexistence path