There are three different meanings that come to my mind quickly.

Yada is a Hebrew word that means to know.

Yada, yada yada. Meaning. A disparaging response, indicating that something previously said was predictable, repetitive or tedious.

Or its an anachronism. Yada is your a dumb a.., well you get the picture.

I was thinking more in the second meaning but choose which ever one you want. I've used it in all three ways.