/usr/lib/python3/dist-packages/Cryptodome/SelfTest/PublicKey/test_vectors/ECC/ecc_p256_private.pem is in python3-pycryptodome 3.4.7-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | -----BEGIN EC PRIVATE KEY-----
MHcCAQEEIFxOQyDvJg+R7Z/Fl67pjII2tg4M7Wksx6BX1eRXmKBSoAoGCCqGSM49
AwEHoUQDQgAEpArVmiBQ6+kkeb1fsWuy5FtkZes8srHv/kI/q+bLdCTbghnvC6uA
rPJv1wWVth/kdg0z7tgN0D0v0N+ye4znXA==
-----END EC PRIVATE KEY-----
|