Importing MRTK packages Unity shows these warnings:

No warnings
Warnings
Import MRTK packages
2017.4.2f2
2017.4.0.0
While we do our best to remove as many of the Build warnings and others, many of the line endings and fbx import warnings can be ignored.
We will be sure to clean these up as soon as possible.
Closing issues older than 180 days. If this is still an issue, please reactivate with recent information.
Most helpful comment
While we do our best to remove as many of the Build warnings and others, many of the line endings and fbx import warnings can be ignored.
We will be sure to clean these up as soon as possible.