pkg time, method (Time) AppendFormat([]uint8, string) []uint8
pkg unicode, const Version = "8.0.0"
pkg unicode, var Ahom *RangeTable
pkg unicode, var Anatolian_Hieroglyphs *RangeTable
pkg unicode, var Hatran *RangeTable
pkg unicode, var Multani *RangeTable
pkg unicode, var Old_Hungarian *RangeTable

says `go` `1.20`, then the program defaults to `panicnil=1`,
matching Go 1.20 instead of Go 1.21.

Because this method of setting GODEBUG defaults was introduced only in Go 1.21,
programs listing versions of Go earlier than Go 1.20 are configured to match Go 1.20,
not the older version.

To override these defaults, a main package's source files
can include one or more `//go:debug` directives at the top of the file