You can use the below RSA key for all clients requiring private key JWT authentication or JAR:
"""
{
"d":"GmiaucNIzdvsEzGjZjd43SDToy1pz-Ph-shsOUXXh-dsYNGftITGerp8bO1iryXh_zUEo8oDK3r1y4klTonQ6bLsWw4ogjLPmL3yiqsoSjJa1G2Ymh_RY_sFZLLXAcrmpbzdWIAkgkHSZTaliL6g57vA7gxvd8L4s82wgGer_JmURI0ECbaCg98JVS0Srtf9GeTRHoX4foLWKc1Vq6NHthzqRMLZe-aRBNU9IMvXNd7kCcIbHCM3GTD_8cFj135nBPP2HOgC_ZXI1txsEf-djqJj8W5vaM7ViKU28IDv1gZGH3CatoysYx6jv1XJVvb2PH8RbFKbJmeyUm3Wvo-rgQ",
"dp":"YNjVBTCIwZD65WCht5ve06vnBLP_Po1NtL_4lkholmPzJ5jbLYBU8f5foNp8DVJBdFQW7wcLmx85-NC5Pl1ZeyA-Ecbw4fDraa5Z4wUKlF0LT6VV79rfOF19y8kwf6MigyrDqMLcH_CRnRGg5NfDsijlZXffINGuxg6wWzhiqqE",
"dq":"LfMDQbvTFNngkZjKkN2CBh5_MBG6Yrmfy4kWA8IC2HQqID5FtreiY2MTAwoDcoINfh3S5CItpuq94tlB2t-VUv8wunhbngHiB5xUprwGAAnwJ3DL39D2m43i_3YP-UO1TgZQUAOh7Jrd4foatpatTvBtY3F1DrCrUKE5Kkn770M",
"e":"AQAB",
"kid":"ZzAjSnraU3bkWGnnAqLapYGpTyNfLbjbzgAPbbW2GEA",
"kty":"RSA",
"n":"wWwQFtSzeRjjerpEM5Rmqz_DsNaZ9S1Bw6UbZkDLowuuTCjBWUax0vBMMxdy6XjEEK4Oq9lKMvx9JzjmeJf1knoqSNrox3Ka0rnxXpNAz6sATvme8p9mTXyp0cX4lF4U2J54xa2_S9NF5QWvpXvBeC4GAJx7QaSw4zrUkrc6XyaAiFnLhQEwKJCwUw4NOqIuYvYp_IXhw-5Ti_icDlZS-282PcccnBeOcX7vc21pozibIdmZJKqXNsL1Ibx5Nkx1F1jLnekJAmdaACDjYRLL_6n3W4wUp19UvzB1lGtXcJKLLkqB6YDiZNu16OSiSprfmrRXvYmvD8m6Fnl5aetgKw",
"p":"7enorp9Pm9XSHaCvQyENcvdU99WCPbnp8vc0KnY_0g9UdX4ZDH07JwKu6DQEwfmUA1qspC-e_KFWTl3x0-I2eJRnHjLOoLrTjrVSBRhBMGEH5PvtZTTThnIY2LReH-6EhceGvcsJ_MhNDUEZLykiH1OnKhmRuvSdhi8oiETqtPE",
"q":"0CBLGi_kRPLqI8yfVkpBbA9zkCAshgrWWn9hsq6a7Zl2LcLaLBRUxH0q1jWnXgeJh9o5v8sYGXwhbrmuypw7kJ0uA3OgEzSsNvX5Ay3R9sNel-3Mqm8Me5OfWWvmTEBOci8RwHstdR-7b9ZT13jk-dsZI7OlV_uBja1ny9Nz9ts",
"qi":"pG6J4dcUDrDndMxa-ee1yG4KjZqqyCQcmPAfqklI2LmnpRIjcK78scclvpboI3JQyg6RCEKVMwAhVtQM6cBcIO3JrHgqeYDblp5wXHjto70HVW6Z8kBruNx1AH9E8LzNvSRL-JVTFzBkJuNgzKQfD0G77tQRgJ-Ri7qu3_9o1M4"
}
"""