I would ignore it if I spotted it once. This is the second time, though, so I probably should point it out: 5 years is a very short time in terms of personal experience and development. While the whole industry moves very fast, it does so thanks to slow, grinding effort parallelized over hundreds of thousands of individuals. For an organization, 5 years is an era. For individuals, it's just 3-6 projects (+/- a few, depending on the context you work in).

TL;DR: "never have encountered in 5 years" is a meaningless data point.

My professional career can legally drink beer since a few years back, yet I'm still regularly hitting "first times" on various things in my day job; I'm also frequently mind-blown reading about others' experiences in domains I never touched. Don't make those "5 years" into a badge to hide behind; use it as a springboard to reach higher.

In this case, try to actively think of uses for the commit history. It's already there; there's an expectation (admittedly, to various degrees depending on context) that it will be maintained. Try to maximize the value you get out of it. Underutilizing a tool you have access to may not be that much of a problem on average, but in some specific circumstances can make a difference between being able to complete a task at all or not. You shouldn't rely on luck to never land in a situation like that: familiarizing yourself with as many potential uses for a tool as possible gives you a better chance of handling it more easily.

EDIT: formatting, last paragraph.