How not to read getenv ( See: https://github.com/git/git/blob/a0a1831b034af10e5d5b37b99489a7558f9cc547/http.c#L831 )

env.c

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    printf("GIT_SSL_NO_VERIFY: %s\n", getenv("GIT_SSL_NO_VERIFY"));

    if (getenv("GIT_SSL_NO_VERIFY"))
        printf("evaluated as TRUE\n");
    else
        printf("evaluated as FALSE\n");

    return EXIT_SUCCESS;
}

result.sh

clang env.c
./a.out
# GIT_SSL_NO_VERIFY: (null)
# evaluated as FALSE

export GIT_SSL_NO_VERIFY=true; ./a.out
# GIT_SSL_NO_VERIFY: true
# evaluated as TRUE

export GIT_SSL_NO_VERIFY=false; ./a.out
# GIT_SSL_NO_VERIFY: false
# evaluated as TRUE

export GIT_SSL_NO_VERIFY; ./a.out
# GIT_SSL_NO_VERIFY: (null)
# evaluated as FALSE

what_just_happened.md

exporting GIT_SSL_NO_VERIFY=true works as expected. Since there is a true, innocent people might think false is the oposite. They will be wrong and you will cause them problems.

Let's don't be lazy and use strcmp

char *gitSslNoVerify = getenv("GIT_SSL_NO_VERIFY");
if (gitSslNoVerify != NULL && strcmp(gitSslNoVerify, "true") == 0) {
    printf("really evaluated as TRUE\n");
} else {
    printf("really evaluated as FALSE\n");
}

Now it works as expected!

export GIT_SSL_NO_VERIFY; ./a.out
# GIT_SSL_NO_VERIFY: (null)
# really evaluated as FALSE

export GIT_SSL_NO_VERIFY=true; ./a.out
# GIT_SSL_NO_VERIFY: true
# really evaluated as TRUE

export GIT_SSL_NO_VERIFY=false; ./a.out
# GIT_SSL_NO_VERIFY: false
# really evaluated as FALSE

unset GIT_SSL_NO_VERIFY; ./a.out
# GIT_SSL_NO_VERIFY: (null)
# really evaluated as FALSE