[development] where to document additions to the core API?

[Derek Wright]

with all the excitement around $node->body (which i share -- way to  
go, everyone!), and looking over http://drupal.org/node/64279  
("Converting 4.7 modules to 4.8/HEAD") i stumbled into a question  
that i don't have a good answer for, and no one in #drupal seemed to  
know at the time, either:

in 4.8, i added a new function to the db_* API, db_table_exists(),  
which is a portable way to find out if a given table exists in your  
DB (i wrote mysql and pgsql versions).  it's a potentially handy  
method, especially for certain hook_update_N() operations if you have  
to deal with some special/weird cases (what i wrote it for in the  
first place), but i'm not sure it's relevant to document it in  
#64279, since it's not really specific to "converting 4.7 modules to  
4.8".  nothing is potentially broken by this addition, no one *has*  
to know the new function exists, etc.  it's *certainly* not  
CHANGELOG.txt worthy.  however, if not in #64279, how are developers  
supposed to know about new functions in the API like this?

1) assume they follow all the core cvs commits closely? ;)
2) spam this mailing list about it and hope everyone who might like  
to know is subscribed?
3) ignore it completely -- if folks need a function like this,  
they'll pour through the source or the doxygen and find it (assuming  
it's named something intelligent).

do we have a place to document additions to the API like this?
do we need a sub-page off of #64279 for additions that aren't  
specific to updating?
am i being crazy, and this should just go directly into #64279, after  
all? ;)

thanks,
-derek (dww)