Trying to commit Git files but getting :: fatal: LF would be replaced by CRLF in <some file in repo>

You might want to set core.safecrlf to "warn", if you want only warning and not a fatal error.

From "git config" mange page:

core.safecrlf

If true, makes git check if converting CRLF is reversible when end-of-line conversion is active. Git will verify if a command modifies a file in the work tree either directly or indirectly.
For example, committing a file followed by checking out the same file should yield the original file in the work tree. If this is not the case for the current setting of core.autocrlf, git will reject the file.
The variable can be set to "warn", in which case git will only warn about an irreversible conversion but continue the operation.

CRLF conversion bears a slight chance of corrupting data.
When it is enabled, git will convert CRLF to LF during commit and LF to CRLF during checkout.
A file that contains a mixture of LF and CRLF before the commit cannot be recreated by git.
For text files this is the right thing to do: it corrects line endings such that we have only LF line endings in the repository.
But for binary files that are accidentally classified as text the conversion can corrupt data.

If you recognize such corruption early you can easily fix it by setting the conversion type explicitly in .gitattributes.
Right after committing you still have the original file in your work tree and this file is not yet corrupted. You can explicitly tell git that this file is binary and git will handle the file appropriately.

Unfortunately, the desired effect of cleaning up text files with mixed line endings and the undesired effect of corrupting binary files cannot be distinguished.
In both cases CRLFs are removed in an irreversible way. For text files this is the right thing to do because CRLFs are line endings, while for binary files converting CRLFs corrupts data.

I prefer identifying the exact files or types of file I want to force the eol with .gitattributes files only (with core.eol settings, which you have), and leave autocrlf to false.

In case of text fiels with mixed eol, this blog post suggests, for instance, to:

If you have Notepad++ installed in your computer, simply follow these steps.

1. Open the file that is having the Fatal issue.
2. Click Edit -> EOL Conversion then select Windows Format or to any that you’re having an issue committing.

Warning, if you have Git 2.17 or 2.18: a regression introduced in 8462ff4 ("convert_to_git(): safe_crlf/checksafe becomes int conv_flags", 2018-01-13, Git 2.17.0) back in Git 2.17 cycle caused autocrlf rewrites to produce a warning message despite setting safecrlf=false.

See commit 6cb0912 (04 Jun 2018) by Anthony Sottile (asottile).
^{(Merged by Junio C Hamano -- gitster -- in commit 8063ff9, 28 Jun 2018)}

git config --global core.safecrlf false

This will disable the crlf fatal warning.

git config core.autocrlf falsegit config core.safecrlf false