antlr-font-lock-keywords-alist is a variable defined in `antlr-mode.el'.
Its value is

((java-mode antlr-no-action-keywords java-font-lock-keywords-1 java-font-lock-keywords-2 java-font-lock-keywords-3) (c++-mode antlr-no-action-keywords c++-font-lock-keywords-1 c++-font-lock-keywords-2 c++-font-lock-keywords-3))

List of font-lock keywords for actions in the grammar.
Each element in this list looks like

If `antlr-language' is equal to MAJOR-MODE, the KEYWORDs are the
font-lock keywords according to `font-lock-defaults' used for the code
in the grammar's actions and semantic predicates, see