What is Inline Frame in c++/VS?

I'm debugging some c++ code. In call stack I have calls with [Inline Frame] before them, what is that and how it's different from normal calls? I'm using Visual Studio 2022 (if you down voting then say why, if it's so trivial then answer, I couldn't find answer anywhere on the internet)

I consider it should be inline function frame.

The document also mentions:

The GetStackTraceEx method provides inline frame support. For more information about working with inline functions, see Debugging Optimized Code and Inline Functions.

Sample: https://developercommunity.visualstudio.com/t/Inconsistent-debug-information-for-inlin/10582059

#include <cassert>
#include <iostream>
#include <set>

using namespace std;

__forceinline void test3(size_t len, set<double>& s) {
    s.insert(0.0);
    while (s.size() < len) {
        auto it = s.rbegin();
        double last = *it;
        s.insert(last + 1.0);
    }
}

__forceinline void test2(size_t len) {
    set <double> s;
    for (int i = 0; i < 100000000; i++) {
        test3(len, s);
    }
    cout << "last: " << *(s.rbegin()) << " size: " << s.size() << endl;
}

__declspec(noinline) void test(size_t len) {
    test2(len);
}

#pragma optimize("", off)

int main(int argc, char** args)
{
    test(1000000);
    return 0;
}

#pragma optimize("", on)

Compile the code: cl source.cpp /Zi /O2 /GL

[inline frame] appears to the left of functions test2 and test3.