Apache license.
Apache Licence is a protocol adopted by Apache, a famous non-profit open source organization. Similar to BSD, the protocol also encourages the code to enjoy and respect the copyright of the original author, and also allows the code to be modified and released (as open source or commercial software).
Conditions to be met:
You need to give the user of the code an Apache license.
If you modify the code, you need to explain it in the modified file.
In the extended code (the modified code and the code derived from the source code), it is necessary to include the description of the agreement, trademark, patent statement and so on specified by the original author in the original code.
Summarized as follows:
If the redistributed product contains a notification file, an Apache license is required in the notification file. You can add your own license in Notice, but it cannot be displayed as a change to the Apache license.
Apache license is also a business-friendly license. Users can also modify the code as needed and publish/sell it as an open source or commercial product.
Commercial software can use Apache protocol to use or modify code.