Missing functions? (custom-initialize-safe-set, custom-initialize-safe-default)

[Adam Porter]

Hi,

Looking in the manual at info:elisp#Variable Definitions, under the
:set keyword, I see this:

‘custom-initialize-safe-set’
‘custom-initialize-safe-default’
     These functions behave like ‘custom-initialize-set’
     (‘custom-initialize-default’, respectively), but catch errors.
     If an error occurs during initialization, they set the
     variable to ‘nil’ using ‘set-default’, and signal no error.

     These functions are meant for options defined in pre-loaded
     files, where the STANDARD expression may signal an error
     because some required variable or function is not yet defined.
     The value normally gets updated in ‘startup.el’, ignoring the
     value computed by ‘defcustom’.  After startup, if one unsets
     the value and reevaluates the ‘defcustom’, the STANDARD
     expression can be evaluated without error.

However, I cannot find those functions defined anywhere, in either
Emacs 25 or 26.  Searching the git history, I see they were added in
2005 in commit 8cb9beb32163fa3ce3b052ced646fd673814ddc6.  Then they
were removed in 2009 in commit
adba8116c3a918f2f091600b60ea1700c9ea7362, however there was no reason
given, and they were not removed from the manual.

I noticed this because, if I understood the manual correctly, they
sounded like they might be useful to fix a problem I was having.

Should these functions be replaced?  If not, why were they removed,
and is there anything that replaces their functionality or obsoletes
them?  Or should they be removed from the manual?

Thanks.