Hi, I remember seeing your posts on WHT
Yes, they auction-off their domains that are registered through GoDaddy (and its related companies). And in recent years, other registrars have also started sending their expired domains to be listed there, I guess because it's been found to be better for them to get more revenue from the expired domains.
And then if someone buys it, the domain gets transferred into your GoDaddy account.
Regarding the timeline, the domain gets listed at
https://auctions.godaddy.com/ around 25 days after the expiry date, and then the auction end time is around day 35. If no one buys it in the auction, then it gets listed as a "buy now" option, starting at $50 (plus renewal fee) on day 36, and going down each day for 5 days, down to $5 (plus renewal fee) maybe around day 40.
Hope that helps