What does Visual Studio mean by normalize inconsistent line endings?

Question

Visual Studio occasionally tells me:

The line endings in the following files are not consistent. Do you want to normalize the line endings?

Answer 1

It's not just Visual Studio... It'd be any tools that read the files, compilers, linkers, etc. that would have to be able to handle it.

In general (for software development) we accept the multiplatform line ending issue, but let the version control software deal with it.