After having looked through quite a number of questions about inserting line breaks within URLs, I'm still wondering about a specific case: manual insertion of line breaks in a URL in biblatex. So the focus here is on manual and on
biblatex. To be even more specific: I'm not using the
hyperref package (since this seems to be a constraint under certain conditions).
So what I would like to know is simply: Is it really impossible to insert manual line breaks in URLs that are part of a biblatex reference?
The reasons why I'm assuming that it is impossible are that this question has no accepted answer (see in particular the last comment by the author) and that neither the answers to this question nor to this question mention a manual solution.