The "clear formatting" button returns bold and italic text to its plain state, as expected. However it also removes any links in the selection, which is not expected, rather there should be a separate "unlink" button to do this job - conceptually I regard a link as an attribute not as formatting.
For example selecting a bolded sentence with an italicised title and a linked word in it. I clicked the clear formatting intending to clear the bold and italic, which it did but it also removed the link. Similarly if using it to remove a link it also removes bold/italic which is unlikely to be the intention.