Saving a filename with a special character in Mac?
Unicode U+002F is equivalent to ASCII 47, or the &quot;slash&quot;/soldus key on your keyboard. Calling it a Unicode special character
is a bit like maître Pathelin in the medieval farce discovering that he was speaking prose; it's just the unmodified output of the key next to the right shift key.
It's not so much that it's a Unicode special character as that it's a special character in the operating system. MacOS has long had a complicated relationship with the slash and colon symbols in path names.
In the command line, / is treated as the directory separator, and cannot be used in filenames. In the Finder, : has been used as the directory separator. A file with a : in its name will display as a / in the Finder, but may produce problems with some program's name safety checks.
If you type at the terminal prompt touch ~/Desktop/test:mytest:2021.html, that file will appear on your desktop as test/mytest/2021.html, but not all programs might be happy about it.