How do LT vs. ST mutual fund capital gains get seperated via the 1099-Div

How do LT vs. ST mutual fund capital gain distributions, get separated via the 1099-div. I'm looking at my 2019 1099-div from my mutual fund company. I notice they lump them all together in box 2a. How does TT know how much is LT vs. ST? Another words, the fund company separates them on its website, yet reports them all in box 2a, which does not contain a differentiation or breakdown.

My understanding is I can report these capital gain distributions on my schedule B, then yes, I know it flows to my schedule d in fact. But how does the software know how much is ST vs. LT. if the fund company itself is not breaking it apart. Unless.........the ST distributions are part of the "non-qualified".....dividends?? Is that how its done?