Look in topic.php and forum.php in your template files, line 3 in the version I checked. Find this:
<?php bb_forum_bread_crumb(); ?>
Make it look like this with your separator in place of *** :
<?php bb_forum_bread_crumb(array('separator' => ' *** ')); ?>
That will change the character for you.
Very good, thank you!
Yet there are pages where the standard separator stays untouched: see as an example the login /bb-login.php page.
Does it mean one have to change it in every template (or so) or is there a central location for such a customization, please?
Apart from the template files forum.php and topic.php that use the bb_forum_bread_crumb() (which just builds the breadcrumb for forums / topics), the separator is also hardcoded into several (all?) other template files to give custom titles, which I’m afraid have to be changed by hand.
The only central location would be the default of bb_forum_bread_crumb(), which you shouldn’t change.
Well, it is good to know, at least.
Thank you.
Programmer’s Notepad + Find in Files = easy finding 
