We're a Shopify partner, and every time there's a conversion on the Shopify website, we send a "pixel event" to our app with a bunch of info, including the Order Name. We use this Order Name as a unique identifier to match with orders we're pulling from Shopify's API.
We're seeing that specific characters in the Order Names are being converted when we fire the event in a function called "handleize". For example, > becomes GT and$becomes-, and spaces are removed. But, we couldn't find any documentation as to how this works or which characters are being converted.