She created an internal spreadsheet allowing Googlers to add their salary information.

Lots of people helped tweak the sheet adding data visualizations, comparisons, etc.

Google management told her they didn't like it, she pointed out that you can't be fired for sharing salary information.

Lots of colleagues were giving her "peer bonuses" for setting this up, but her manager kept blocking them, something which is apparently unheard of to the point that most people didn't know they could be blocked.

By the time she left, 5% of staff were apparently using the sheet.

Even more TLDR: Nothing particularly happened except that Google showed they dislike colleagues talking about salaries.