what does this mean: Migrated from user-supplied source citation: urn:familysearch:source:3244478107. How do I find the information relating to that number?
The migration of sources indicate that those sources were brought to this web site , Familysearch.org from our previous web site new.family search.
Migration of nFS legacy sources from new FamilySearch
We hope this link will explain the process.
Thank you for being concerned about sources. They are vital to prove the validity of a person in any genealogical site
I am just another 'lowly' User/Patron ...
And, further to what has already been proffered by 'NidaFL' ...
Regarding your second 'Question' of "... How do I find the information relating to that number ..."
Short Answer: You CANNOT.
Those references were from the forerunner of "Family Tree"; being, "New.FamilySearch".
The were transferred across, from "New.FamilySearch", to "Family Tree", in 2014.
The "Detail" that you 'see', is ALL we get.
That 'number' relates to the reference ONLY (and, User/patron); and, NOT the "Detail" associated with such.
[ I know; as, I has 'seen' many of such that relate to ME ... ]
I hope this helps, somewhat.
Because the source structure in Family Tree is so different than the source structure in New Family Search, the migration process could not differentiate between a real source and cryptic junk. I have only very rarely run across any of these migrated source that are of any use at all and almost always just detach them.
Like Gordon Collett, I also detach most migrated "source" links, as they contain no information and merely create the sometimes extremely false appearance that the profile is well documented.
Even worse, some of those links that appear to contain information contain false information.