Querying an exact match of a few strings on Google shows me that Slack is the very first example given in the blog post. For additional confirmation, the "6-byte message" screenshot lists an xoxc token and rich_text object, both of which you will frequently encounter in the Slack API. To be honest, I was expecting it to be Jira at first since I was unaware of Slack's size.

Searching for an exact match of "PRL_ERR_WEB_PORTAL_UNEXPECTED" gives away Parallels as the first example of a hard-coded HTTPS timeout.

So on, so forth.