19th Century Retro is a re-design of an official German font style (called ‘Fraktur’) which was used in official documents in the 19th and early 20th century.
There is an alternative small letter ‘s’ which you generate by typing the @ sign. This alternative letter was the original small letter s which was printed in the middle and at the beginning of a word originally (for example in the words ‘slightly’ and ‘best’). However, if the s was at the end, the normal small letter s was used (for example in the words ‘it’s’ and ‘columns’). For readability reasons I decided to put the normal small letter s onto the s-key on your keyboard.