Sure. MKVTools http://www.emmgunn.com/mkvtools-home/mkvtools-downloads/ does that (select subtitle track with a check box, click "extract selected tracks" on the bottom of the window or use the "send to SUBtools" option if you decide to install SUBtools as well.
I will go with the from an unidentified developer warning you get from the apple lock down of installing programs from outside the app store.. I too have used it for years and it works great.
I will go with the from an unidentified developer warning you get from the apple lock down of installing programs from outside the app store.. I too have used it for years and it works great.