The [GODEBUG History](#history) gives the exact defaults for each Go toolchain version.
For example, Go 1.21 introduces the `panicnil` setting,
controlling whether `panic(nil)` is allowed;
it defaults to `panicnil=0`, making `panic(nil)` a run-time error.
Using `panicnil=1` restores the behavior of Go 1.20 and earlier.

When compiling a work module or workspace that declares

pkg text/template/parse, type TextNode struct, embedded Pos
pkg text/template/parse, type Tree struct, ParseName string
pkg text/template/parse, type VariableNode struct, embedded Pos
pkg time, const ANSIC = "Mon Jan _2 15:04:05 2006"
pkg time, const April = 4
pkg time, const August = 8
pkg time, const December = 12
pkg time, const February = 2
pkg time, const Friday = 5
pkg time, const Hour = 3600000000000