License.txt doesn't define the licensor / copyright holder, nor the years

[lickel]

A common thing for Apache licensed software is to provide the "short" version in the readme.
This can easily be copied for open source attribution pages.

The source code would suggest this is that text:

Copyright (c) 2018 Apple Inc. and the Swift Logging API project authors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

[weissi]

CC @tomerd