CotEditor can inspect the information about the selected character. Select exactly a single character and choose the Inspect Character command in the Text menu or press the Command-Option-I keys.
The inspector shows: the character in close-up, the Unicode code point, the Unicode character name, block name, general category, and the Unicode version that introduced the character. It also shows the UTF-16 codes of each character in braces if the character is a surrogate pair. If the selected letter consists actually of multiple Unicode characters, only the code points and Unicode names appear.