How to disable searching in invisible text? (setq search-invisible nil) has no effect #1739
It's can also be used in folded outline buffer (headings). The following enables outline for all program mode.
swiper will be much better than isearch
It just customizes the outline regexp for heading, so for elisp mode you have heading like:
for python mode it is:
If search-invisible is enabled, we can fold the outline and easily search in those headings.