What does in .gitattributes * text=auto

in_gitattributes_text_auto.txt

// Auto detect text files and perform LF normalization
* text=auto

In a .gitattributes file, setting `text=auto` means that the path is marked for automatic end-of-line normalization. 
If Git decides that the content is text, its line endings are normalized to LF on check-in. 
This setting allows fine-grained control over how line endings are converted.

https://stackoverflow.com/questions/21472971/what-is-the-purpose-of-text-auto-in-gitattributes-file

from that SO question:
"
Here's what * text=auto does in my words: when someone commits a file, 
Git guesses whether that file is a text file or not, and if it is, 
it will commit a version of the file where all CR + LF bytes are replaced with LF bytes. 
It doesn't directly affect what files look like in the working tree, 
there are other settings that will convert LF bytes to CR + LF bytes when checking out a file.
I would not recommend putting * text=auto in the .gitattributes file. Instead, I would recommend something like this:

*.txt text
*.html text
*.css text
*.js text

This explicitly designates which files are text files, 
hich get CRLF converted to LF in the object database (but not necessarily in the working tree). 
We had a repo with * text=auto, and Git guessed wrong for an image file that it was a text file, 
causing it to corrupt it as it replaced CR + LF bytes with LF bytes in the object database. 
That was not a fun one to debug.
If you must use * text=auto, put it as the first line in .gitattributes, so that the later lines can override it. 
This seems to be becoming an increasingly popular practise.
"

CR vs CRLF
//Only Windows (considering main-stream OSs only) is using CRLF, Linux uses LF.
LF means Line-Feed.
CR means Carriage Return.

https://stackoverflow.com/questions/6521685/why-does-windows-use-cr-lf
from that SO question:

"Historically when using teletypes CR would return the carriage to the first position of the line 
while LF would feed to the next line. 
Using CR+LF in the file themselves made it possible to send a file directly to the printer, 
without any kind of printer driver."