A popular library installation technique is to download the library via GitHub's Clone or download > Download ZIP and then use the Arduino IDE's Sketch > Include Library > Add .ZIP Library on the downloaded file. This requires the library to be in the root of the repository, not in a subfolder. If the library is not in the root of the repository this installation technique fails:
Specified folder/zip file does not contain a valid library
A popular library installation technique is to download the library via GitHub's Clone or download > Download ZIP and then use the Arduino IDE's Sketch > Include Library > Add .ZIP Library on the downloaded file. This requires the library to be in the root of the repository, not in a subfolder. If the library is not in the root of the repository this installation technique fails:
This move is also required if you wanted to add your library to the Arduino Library Manager index, which provides an even easier installation option.