I got my facebook pixel installed but cannot figure out how to install the required microdata. It idiotic if Etsy has no way to do this because otherwise, why allow the pixel install??
I am unaware of this functionality being available.
As for what the pixel installation is for, it's for tracking. From Help here:
https://help.etsy.com/hc/en-us/articles/360000343468-Managing-Marketing-Settings?segment=selling
"If you have paid advertising campaigns through Facebook or Google, you can track the conversion of these campaigns by adding your conversion tags or codes from the Marketing tab of your Pattern Dashboard.
Access your tracking pixel by going to the Facebook Pixel section in the Ads Manager. If you need help accessing your pixel tracking code, refer to these instructions from the Facebook Help Center.
Copy your pixel number.
I did get my product catalog onto FB and IG, but I did not use the FB pixel. I downloaded my listings as a .csv file which I had to edit and then submit. It took several attempts. We will see if it was worth it.