libmpfr6 4.0.0-5 (arm64 binary) in ubuntu bionic

 MPFR provides a library for multiple-precision floating-point computation
 with correct rounding. The computation is both efficient and has a
 well-defined semantics. It copies the good ideas from the
 ANSI/IEEE-754 standard for double-precision floating-point arithmetic
 (53-bit mantissa).