OurBigBook
Lists other sections that link to the current section.
E.g. in:
the page since those pages link to the
= tmp
== tmp 1
=== tmp 1 1
=== tmp 1 2
\x[tmp-1]
== tmp 2
\x[tmp-1]tmp-1.html would contain a list of incoming links as:tmp-1-2tmp-2
tmp-1 ID.