It was more than just tab conversion. For example, it decided on its own that:

if(...) {
    ...
}
else {
    ...
}

would look better like:

if(...) {
    ...
} else {
    ...
}

I mean I guess I could live with that, but really? I imagine there's some config where you can disable all this, but it just doesn't seem worth some giant git commit every time I touch a file with the editor.