Extracting data from a TWRP backup How can I extract individual files from a backup created with TWRP? I’ve come across this answer, which is about extracting an APK from the system partition. However, I want to extract files from /data, which gets split across several files in the backup.
cat data.ext4.win??? | tar xvfi -
What this does is concatenate each file matching the pattern data.ext4.win??? and then pipe the concatenated files to tar for extraction. the - as the filename tells tar to extract from stdin. The i option ignores zero blocks which will be in between each archive file concatenated.
In this example I used the ext4 formatted data partition. Change data.ext4 to match the partition you are extracting.
Disclaimer: This has not been tested in a windows environment.

For a less hacky solution found here
for f in data.ext4.win???; do tar xvf &quot;$f&quot;; done
This is a bit simpler without relying on the ignore zeros option of tar to operate properly

Edited to reflect davidgo's comment.
31-Jan-2020 Edited to reflect Code Bling's comments.
17-Feb-2021 Edited to reflect alecxs's comments.