On Meta Stack Exchange you can ask questions about software that drive the SE network.
But as it is closed source and only an SE Dev or Sysop could answer it might depend on how much they want to share or if the feature owner find the time to write a good answer.
Examples of good questions are:
How does Stack Exchange work around the lack of Redis clustering?
Does StackExchange have 1 multi-tenant environment, or many single-tenant environments?
Does Stack Exchange use caching and if so, how?
Who made the 2013 Winter Bash snowflake script?
Markdown formatting bug with code blocks in lists
How much bandwidth does SE eat up?
(and this selection doesn't mean I don't like contributions by other Devs)
For your example question I think their implementation is close to what is in SEDE which means there is a row added to the PostLinks table for every link.