How do I delimit a lookup multi-select field with line breaks instead of commas?

How do I delimit a lookup multi-select field with line breaks instead of commas?

Hi

I understand there is no direct way to make each entry of a multi-select field appear on a new line when viewed, i.e.

one
two
three

rather than

one, two, three

However, there is a workaround using the replaceAll function and the <br> HTML tag, which I don't fully understand. Could someone please explain this option? The multi-select field I have uses a lookup from another form to populate the list.

Many thanks

Martin