tools:ignore can be used in xml files to dismiss lint warnings.
BUT dismissing lint warnings with this technique is most of the time the wrong way to proceed.
A lint warning must be understood and fixed... it can be ignored if and only if you have a full understanding of it's meaning and a strong reason to ignore it.
Here is a use case where it legitimate to ignore a lint warning:
Then you can do this in your manifest : (i.e. requesting the protected permission and ignoring the lint warning because you know that in your case the permission will be granted)
<manifest xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" ...> <uses-permission android:name="android.permission.SET_TIME" tools:ignore="ProtectedPermissions"/>