Trying to migrate a large project from 2017+Asset to 2018+Package the GUID migration tool would take about 30 hours because it parses .blend files, by editing the source to and adding .blend to the exclusions right after .fbx, and now I can migrate the assets folder in 10 minutes 
I made the suggested change which will be included in the next release of the TMP package.
Please use the “TextMeshPro” prefix on TMP related posts instead of Feedback (even if it is feedback or feature requests) as this will significantly decrease the chance of me missing the post.
Thanks Stephan. I also noticed sbsar was being parsed, and various other files (TMP, etc). I’m not sure if it makes sense to rather be explicit in the extensions? .unity, .asset, .prefab? Can a reference exist anywhere else?
Noted about the prefix!
Saw your post earlier this week but didn’t have time to reply at the time.
There are more like .anim so I would have to take the time to compile a list of those potential file extensions. As the list of potential types grows, it would make sense to only scan known extension types but then again, this is a temporary thing as this conversion if only needed once when migrating from legacy versions to package manager versions of TMP.