Open source obligations must pass the BSD open source agreement, because the BSD open source agreement is an agreement that gives users great freedom. Basically, users can "do whatever they want" and can use it freely, modify the source code, or re-release the modified code as open source or proprietary software.

But the premise of "doing whatever you want" is that when you publish code that uses the BSD protocol, or develop your own products based on the BSD protocol code, you need to meet three conditions:

1. If the re-released product contains source code, the source code must contain the BSD protocol of the original code.

2. If only a binary class library/software is redistributed, the BSD protocol in the original code needs to be included in the documentation and copyright statement of the class library/software.

3. Do not use the name of the author/organization of the open source code or the name of the original product for marketing purposes.

Similar to the BSD open source agreement is the Apache License 2.0.

Apache License is a protocol adopted by Apache, a well-known non-profit open source organization. This agreement is similar to BSD. It also encourages code owners to share and respect the copyright of the original author, and also allows code modification and re-release.

The conditions that need to be met are also similar to BSD:

1. The user of the code needs to be given an Apache License.

2. If you modify the code, you need to explain it in the modified file.

3. In the extended code (code modified and derived from source code), the agreement, trademark, patent statement and other instructions specified by the original author need to be included in the original code.

If the re-released product contains a Notice file, the Notice file needs to contain an Apache License. You can add your own license to the Notice, but it cannot appear to be a change to the Apache License.

The Apache License is also a license friendly to commercial applications. Users can also modify the code to meet their needs when needed and publish/sell it as an open source or commercial product.