Some time ago I wrote about new options for explains – one that prints settings that were modified from default.
This looks like this:
Aggregate (cost=35.36..35.37 rows=1 width=8) -> Index Only Scan using pg_class_oid_index on pg_class (cost=0.27..34.29 rows=429 width=0) Settings: enable_seqscan = 'off'
Finally, today, I pushed a change that displays them on explain.depesz.com. To make it more usable, it will also provide links to documentation about each such options.
For example, check this plan.
Hope you'll find it useful.