Some past threads:

SHA-1 collisions now cost $45k [pdf] - https://news.ycombinator.com/item?id=23350223 - May 2020 (62 comments)

The first chosen-prefix collision for SHA-1 - https://news.ycombinator.com/item?id=21979333 - Jan 2020 (352 comments)

Abusing SHA-1 collisions for Chromium updates - https://news.ycombinator.com/item?id=20114809 - June 2019 (36 comments)

A SHA-1 chosen-prefix collision attack - https://news.ycombinator.com/item?id=19907127 - May 2019 (71 comments)

From Collisions to Chosen-Prefix Collisions Application to Full SHA-1 [pdf] - https://news.ycombinator.com/item?id=19878917 - May 2019 (18 comments)

SHA-1 Collision Detection on GitHub.com - https://news.ycombinator.com/item?id=13917990 - March 2017 (90 comments)

Linus' reply on Git and SHA-1 collision - https://news.ycombinator.com/item?id=13719368 - Feb 2017 (262 comments)

When Will We See Collisions for SHA-1? (2012) - https://news.ycombinator.com/item?id=13719079 - Feb 2017 (1 comment)

Announcing the first SHA-1 collision - https://news.ycombinator.com/item?id=13713480 - Feb 2017 (485 comments)

How would Git handle a SHA-1 collision on a blob? - https://news.ycombinator.com/item?id=13547348 - Feb 2017 (5 comments)

Why it’s harder to forge a SHA-1 certificate than to find a SHA-1 collision - https://news.ycombinator.com/item?id=10778773 - Dec 2015 (43 comments)

The Cost of Creating Collisions Using SHA-1 - https://news.ycombinator.com/item?id=8629906 - Nov 2014 (9 comments)

When Will We See Collisions for SHA-1? - https://news.ycombinator.com/item?id=4618069 - Oct 2012 (51 comments)