This variable holds an alist associating special variable symbols to forms to evaluate. Special variables named in this list will be locally bound in the new thread before it begins executing user code.

This variable may be rebound around calls to make-thread to add/alter default bindings. The effect of mutating this list is undefined, but earlier forms take precedence over later forms for the same symbol, so defaults may be overridden by consing to the head of the list.