Is the tıtle purposely ambiguous for clicks? They obviously mean each liquid bottle has to be max 100 ml, not that the total amount of liquids allowed is 100 ml, right?
ı is not a Cyrillic letter, it's a letter for the Latin alphabet that is most commonly used in Turkish.
It exists in non-modern Russian and modern languages - such as Ukrainian - Cyrillic alphabets in various forms, sometimes with top and bottom horizontal strokes, sometimes just like this.