[O] org-link-to-org-use-id question

[François Pinard]

Hi, Org friends.

I'm just noticing that ID: properties are now being created whenever I save
a link.  I presume this is a recent change.

The ID does not encode the file, so I'm tempted to presume that Org
ought to read the target Org files for discovering where are the IDs.
As Org is surely not going to read all my Org files at start (it might
not even have a clue to where I saved them), I wonder how this mechanism
works.  Would someone be kind enough to enlighten me?

François