It's a "typical Apple touch." That's what developer Matt Gemmell said about something he noticed in Touch ID, and we agree. When you have your Touch ID setting open and have multiple fingerprints registered, touching the Home button will highlight the relevant profile.

Here's Mr. Gemmell's tweet:

Great tip about 5s fingerprints settings screen. Put fingers on Home button to briefly highlight relevant profile. Typical Apple touch. — Matt Gemmell (@mattgemmell) October 1, 2013

Great observation, Mr. Gemmell! It's a subtle effect, but quite useful if you're managing multiple fingerprints. Here's how it works:

Since Touch ID is still new territory, we're going to walk through step-by-step. In Settings > General, there's a section called Passcode & Fingerprint, as shown in the image below:

Passcode & Fingerprint

On this screen, there's a section called Fingerprints, as shown below.

Fingerprints

Tapping that gives you the Fingerprints screen, as shown below. In this example, we have three fingerprint profiles attached to the iPhone 5s in question.

Three Fingers

That's great, but if you want to manage those fingerprints—for instance, delete one—and you can't remember which is which, Apple provided a way to tell.

When you're on the screen above and you touch the home button with one of the fingers stored in your iPhone, it will very briefly flash the profile it's attached to, as shown in the image below.

Ah, It's this finger!

We say "briefly flash," but the flash is more like a "highlight by briefly making it gray."

It's handy, it's subtle, and it's a nice touch.

Dave Hamilton contributed to this article.