Apparently I had tinkered with this some time in 2015. I have no recollection of it. Maybe I didn't like it, or maybe it was just an aborted project. It seems neat, I should look into it again some day.
Here's a script I made to start it up:
# Note - Start as a regular user # You can change settings with #sudo dpkg-reconfigure -plow i2p \rm --force \ ~/.i2p/i2p.pid \ ~/.i2p/i2p.status \ ~/.i2p/i2p.java.status \ ` # ` \i2prouter start