Yogh (Ȝ ȝ) is a letter used in [Middle English]
?, representing y and various velar
?-ish sounds.
(Velar sounds are usually made when the back of the tongue is pressed against the soft palate. They include the /k/ in cat, the /g/ in girl and the /ng/ in hang.)
It is shaped like the Arabic numeral 3, which is sometimes substituted for the character in online reference works. It would seem there is some confusion about the letter in the literature...
For example:
[La3amon]