1. **Open source code**: Some companies will make some of their code public in an open source manner, such as Google's TensorFlow and Apache's open source projects. You can learn about the development style and technology stack of related companies through these projects. 2. **GitHub**: Developers of many companies will make personal or company project codes public on GitHub. You can find relevant code repositories by searching keywords or company names. 3. **Code analysis reports**: Some security companies or research institutions will publish code analysis reports, which include security assessments and analysis of well-known company codes. You can learn about the security and development quality of the code through these reports. 4. **Conferences and seminars**: Attending technical conferences and seminars can listen to speeches by company engineers and learn about their development experience and technology choices. 5. **Online courses and tutorials**: Some companies will provide online courses or tutorials, including their development experience and technology stack. You can learn about the development methods of related companies through these resources. 6. **Cooperation and communication**: If you have the opportunity to cooperate or communicate with well-known companies, you can ask them to share some code or development experience. 7. **Check the company's recruitment information**: The company's recruitment information usually includes some technical requirements and development languages, which can be used to understand the company's technology stack. 8. **Research papers**: Some companies will publish research papers that include their development experience and technological innovations. You can learn about the company's technical direction through these papers. 9. **Participate in hackathons**: Participate in hackathons to communicate with company engineers and learn about their development experience and technology choices. 10. **Check out the company's technical blog**: Some companies will share their development experience and technology choices in technical blogs, and you can learn about the company's technology stack through these blogs.