Where's the logic for the collaboration in real time html insertion?

[raxhacks]

I want to know in which file I can finde the logic that makes it possible to distinguish between one span tag and another when working in real time collaboration. For example, something like this:
<div aria-live="assertive" id="magicdomid53" class="ace-line"><span class="author-a-vxnfz84zz80zz73z74z87z6z89zz70zz85zdz70z">asasasasassd</span><span class="author-a-iz86zgibpz75zx9z68zk0nvcz78z">sdsdsdsdsdsds</span><span class="author-a-vxnfz84zz80zz73z74z87z6z89zz70zz85zdz70z">asdasasasasasasasdsd</span></div>

as you can see, there is one initial span with an author 1, then the middle span with author 2, finishing with the last span with author 1 again. I want to know where I can find this logic or how can I implement something similar when pasting text in the document.