What is meant by stock Android version?

Related questions

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5. Is it safe to install custom ROM?
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Tags

1. #skins
2. #known
3. #overall
4. #designed
5. #vanilla
6. #stock
7. #huawei
8. #basic
9. #version
10. #manufacturers
11. #change
12. #experience
13. #quite
14. #device
15. #developed
16. #google
17. #android
18. #meaning
19. #installed
20. #unmodified