RE: How can I discover group name?

[Drew Adams]

> Within "M-x customize"  I found "Text" group.

I don't see that group, with `emacs -Q'.  Perhaps it comes from
some library that you are using?

What does `M-x customize-group RET TAB' tell you?
That's how to discover group names.

> I'd like to add my group to this group. Unfortunately this was failed:
>   (defgroup xxx nil
>     "xxx-mode customization."
>     :group 'text)
              ^^^^  'Text, not 'text, if "Text" is the group name.

> Searching around gave working piece:
>   (defgroup xxx nil
>     "xxx-mode customization."
>     :group 'wp)
> 
> How can I guess "wp" name from customize buffer content?

What is the relation between this and group "Text"?
What do you see in the Customize buffer?

> Is that from somewhat historical reasons?

Is what from somewhat historical reasons?

The question is unclear.