Question about attribution

[carlosmintfan]

If I copy the code from a hero on https://getbootstrap.com/docs/5.3/examples/heroes/ and modify the text and maybe some classes, but still leave most classes of the code as it was – do I have to attribute that this is adapted from CC-licensed code or is it small enough to be left out?
If I copy the sample code for a checkbox on https://getbootstrap.com/docs/5.3/forms/checks-radios/ and modify the text, then I assume I don't have to attribute that small code which you maybe even cannot "properly do differently"?
Where is the line?