Short answer
Google Sheets doesn't include that as a built-in feature. Google added a similar feature in 2019: the cell's edit history.
Explanation
Google Sheets UI access to the revision history is through File > Revision History. At this time it doesn't include an equivalent to git blame
but Google recently (mid 2019) added an easy way to check cell history. Just right click on a cell and select Show edit History.
There is a free third-party developer tool called BetterLog that could help create a log for changes made by using Google Apps Script but be aware that Google Apps Script's triggers work on a "best effort basis" (meaning that some changes could not fire the corresponding trigger causing that some logs be missed).
Another alternative is to use the Google Drive API to access the Revision resource. This way, you could manipulate in a way similar to git blame
.
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