Doraemon 3 Debug Menu
Channel: Zoinkity
Date: 2018-02-09

※Captions contain additional info!

Not to be confused with the in-game debug menu, this thing is suspiciously similar to the one in Densha de Go! 64 down to a significant amount of its code being 100% identical.

Just like DdG, the root menu is 0x5A.  However, as far as I know you can't normally boot into it.
It has an identical VRS test menu (and this explains why the labels were Doraemon character names) and the same weather strings as keys.  VRS can be on any port except port 1.
Transfer Pak debug is unique to this.  For whatever reason it crashes if I have any normal controller plugged in without a transfer pak (VRS is okay).  Pressing A would iterate between each of the six PIF channels.  64GB is init and errors displayed if it's on port 4 and you press A enough, but don't have enough stuff handy to illustrate it here.
System Test appears to be DdG's block test and crashes if selected.  Looks like it tries to pull bad resources.