[jkafjanvnfaf]

It's new because it makes no sense.

There already is an implicit "branch" on every array access in C, it's called an access violation.

Do they test for a segfault on every single array access in the code base? No? Then they don't really have 100% branch coverage, do they?

[prein]

Take a look at their description of how SQLite is tested: https://www.sqlite.org/testing.html

I think a lot of projects that claim to have 100% coverage are overselling their testing, but SQLite is in another category of thoroughness entirely.