How does version control work (for dummies)?

Question

linux

Let's take Linux for example. Clarifying questions:
- how is the code closed in production? A bunch of people work on different things, someone else's code rules. How do various edits merge (in time, by completion, by authorship)? Why are there no programming conflicts when merging?
- how is security ensured? For example, I, a bad person, started to implement a feature. In fact, I implemented it, but I added non-obvious dirty tricks (backdoors or knockers) to my thousands of code. Carefully hiding them behind the jungle

Answer 1

A small responsible group of people checks all edits and includes them in production, resolving conflicts along the way or sending them for revision.

Answer 2

Conflicts arise when branches are merged and they are manually corrected by developers. The code is divided into branches in most cases, according to the readiness for use and the functionality present. Security is ensured through code review, that is, a thorough examination of the code written by other participants.

Answer 3

All questions are administrative, respectively, they are solved by administrative methods, vcs itself has nothing to do with it.
One of the possible solutions, typical.
1. The branch responsible for the current production collects the changes into the current release and merges. Mandatory one, or a group of authorized persons.
2. Regular code-review sessions
3. The organization within the project can be any, a branch for a feature, a tag for a release... But deploy versions are collected by a specially dedicated person, for example, in our case, this is anyone in turn.