This tool can convert a JWK Set (https://tools.ietf.org/html/rfc7517) to standard PEM keys.
Install the requirements for jwks2pem
pip install -r requirements.txt
Simple example given a keystore keystore.jwks
python3 jwks2pem.py [-h] --input keystore.jwks --output key
this produces one PEM file per key in keystore.jwks
with a name of key_0.pem
... key_n.pem
and shows the following message if successful:
1 keys successfully converted to PEM format