mongoc_uri_option_is_utf8(3) on Linux
The text c2365dd9f5fc, as Debian 9 (Stretch) shipped it.
Returns true if the option is a known MongoDB URI option of string type. For example, "replicaSet=my_rs" is a valid MongoDB URI option, so mongoc_uri_option_is_utf8 ("replicaSet") is true.