Man pages matching name go-testflag in section 7:

go-testflag.7.en	debian 10 / gccgo-go
go-testflag.7.en	debian 10 / golang-go
go-testflag.7.en	debian 11 / gccgo-go
go-testflag.7.en	debian 11 / golang-go
go-testflag.7.en	debian 12 / gccgo-go
go-testflag.7.en	debian 12 / golang-go