I don’t think the solution you mentioned worked for a while; it may (inadvertently?) work on some previous versions of Firefox, but it does not look like the one you would expect to complete a task ( pre-wrap should not be expected to break words).
A way to force Firefox to treat the dot as a valid direct line break option is the <wbr> , but not in any specification, but widely supported. Usually it’s best to use it by inserting it at suitable points, but, in extreme cases, you can even put it between any two characters (presumably, you need to use preprocessing, server-side scripting or client-side JavaScript for this).
source share