where are docs on COMPAT_* and pkgsrc/emulators/compat_*?

I was googling about NetBSD's backward binary compatibility
but didn't see 
any one webpage about it.

Do we have any single document that explains kernel COMPAT_*
and using 
pkgsrc/emulators/compat_*?

With examples...

  Jeremy C. Reed

"Jeremy C. Reed" <reedreedmedia.net> wrote:
> I was googling about NetBSD's backward binary
compatibility but didn't see 
> any one webpage about it.
> 
> Do we have any single document that explains kernel
COMPAT_* and using 
> pkgsrc/emulators/compat_*?
> 
> With examples...

I don't know about single document, but options(4) and
compat_*(8) man
pages are containing a lot of glue which you're looking
for...

	- M.