If I check official documentation, I can see a property called HTML:
Name | Type | default | Description
----------------------------------------------------------------------------
html | boolean | false | Insert html into the tooltip.
If false, jquery's text method
will be used to insert content
into the dom. Use text if you're
worried about XSS attacks.
It says, "insert html into the tooltip", but the type is boolean. How can I use complex html inside a Tooltip?
This parameter is just about whether you are going to use complex html into the tooltip. Set it to true and then hit the html into the title attribute of the tag.
See this fiddle here - I've set the html attribute to true through the data-html="true" in the <a> tag and then just added in the html ad hoc as an example.
In bootstrap 5, the attribute has been renamed to data-bs-html.