brainpoolP192r1 is the 192-bit Brainpool curve of RFC 5639, with parameters derived verifiably from the digits of π and e.
brainpoolP192r1 is a short Weierstrass curve y² = x³ + ax + b over a 192-bit prime field with a 192-bit prime-order subgroup and cofactor 1; its estimated security level is 96 bits. Status: deprecated, do not use for new keys.
The Brainpool curves (RFC 5639) were generated in a verifiably pseudo-random way: the primes come from the digits of π and the curve coefficients from the digits of e, so anyone can recompute them (RFC 5639 Appendix A). brainpoolP192r1 is the 192-bit random curve; it has prime order (cofactor 1) and about 96 bits of security.
At about 96 bits of security it is too small for new keys (NIST SP 800-57 requires at least 112 bits). NIST SP 800-186 lists the Brainpool curves solely for interoperability.