Fingerprint for 886DDD89 key on web page
While the signing keys for most of the distributions are found at:
The fingerprint for the 886DDD89 (deb.torproject.org archive signing key) is not found there. Which it probably should be.
Neither is it shown on the debian install page, except hidden away in the command:
gpg --export A3C4F0F979CAA22CDBA8F512EE8CBC9E886DDD89 | sudo apt-key add -
I would recommend adding the fingerprint and a short note on how to check it to both places.