[Libreoffice] What is "important bug fixes" for bugfix release?

Hello all,
I wonder what are the criteria specifying whether a bug should be
fixed in which stable branch, if it affects all?
Such as, in my understanding, fdo#33149 is fixed in master after
branching -3-3 but before -3-4, so -3-4 has it but -3-3 not.
I've found in wiki [1] that 3.x.y has "only important bug fixes ...",
but the point is: what is "important"?

I think the bug report will report earliest version [2] (which seems
impossible, because I think there is a few people that have old
versions), the patch should go into that earliest branch, then merge
into more update branch ...

[1] http://wiki.documentfoundation.org/ReleasePlan/3.3
[2] http://wiki.documentfoundation.org/BugReport_Details#Version

Best Regards,
-- 
Korrawit Pruegsanusak