Selecting elements of a list based on specific elements of their sublist

There are lots of different ways. The most common ones would be:

Cases[l, {_, _, _, _, "FALSE", _, _}]

{{789, "style", "", "url", "FALSE", "FALSE", "TRUE"}, {223, "style", "", "url", "FALSE", "FALSE", "TRUE"}}

Select[l, #[[5]] == "FALSE" &]

{{789, "style", "", "url", "FALSE", "FALSE", "TRUE"}, {223, "style", "", "url", "FALSE", "FALSE", "TRUE"}}

l//Pick[#, #[[All,5]], "FALSE"]&

{{789, style, , url, FALSE, FALSE, TRUE}, {223, style, , url, FALSE, FALSE, TRUE}}