It seems you ask for a specific key/value field like this:

https://sources.debian.org/src/pypass/0.2.1-2/pypass/command.py/#L193

But there are only three specific fields you can ask for:

https://sources.debian.org/src/pypass/0.2.1-2/pypass/entry_type.py/#L23

I thought "no worries, I'll just make my own subclass of that",
except it's also baked in here:

https://sources.debian.org/src/pypass/0.2.1-2/pypass/passwordstore.py/#L120

My use case is, certain governments require me to input additional passwords,
and I want to use key/value pairs for them, e.g.

    $ pass show tax-haven.ai
    diminish canopener blooper radiation direction paving
    url: https://www.tax-haven.ai/login.asp
    login: twb
    What was your first pet's maiden name?: directed darkness oxidant reborn agreeing cozily
    What band were you bassist for when the Americans faked the moon landing?: nanny molehill jokingly define lyrics skeleton
    What is your favourite California penal code section?: satin linguini frayed nervous script ought
    What is the problem with kids today?: moonlight uniformed concierge flatware flattered unboxed
    Ты не забываешь деньги?: Гусары денег не берут!

...and then, I guess, have some way to get those back out without going maaaaaaaad.
I haven't worked out that part yet.