You can now check out my new unlisted video on Youtube,
"Formalizing Geometric Proof Schwabhäuser 4.6 in the Metamath Proof Explorer", at:
https://youtu.be/-DTBRvRlflA
If no one finds any serious problems with it soon, I plan to list it.
If you *do* find any problems with it, let me know.
--- David A. Wheeler