Andrew Robbins <contact@andrewrobbins.info> writes:

The ERC variable "erc-button-google-url" should not refer to a
specific search engine in its name and certainly not a
privacy-disrespecting one at that in a GNU program[1].

I would suggest renaming the variable to something more generic
such as "erc-button-web-search-url" or "erc-button-search-url"
and changing the default value from
"http://www.google.com/search?q=%s" to any of the following (or
similar) at the developers' preference:

* "http://duckduckgo.com/?q=%s"

This is now fixed in Emacs 27.1.

-(defcustom·erc-button-google-url "http://www.google.com/search?q=%s" 
+(defcustom·erc-button-search-url "http://duckduckgo.com/?q=%s" 
 · "URL used to browse Google search references. 
 %s·is replaced by the search string." 
+· :version "27.1"