Combine mangos, pineapple, and cider vinegar in a stockpot over medium-high heat. Bring to a simmer; mash mangos and pineapple to a chunky consistency with a potato masher. Stir in sugar until dissolved.

Stir liquid pectin and habanero chile halves into the stockpot. Bring to a roaring boil, stirring frequently. Cook, stirring regularly, until jam thickens, about 2 minutes. Remove chile halves. Discard 6 chile halves; chop 2 half and stir back into the stockpot.

Sterilize 8 half-pint jars and lids in boiling water for at least 5 minutes.

Ladle hot jam into the heated, sterilized jars, filling to within 1/4 inch of the top. Run a clean knife around the insides of the jars to eliminate any air bubbles. Wipe the rims of the jars with a moist paper towel to remove any food residue. Top with the lids and screw on the rings.

Place a rack in the bottom of a big stockpot and fill halfway with water. Bring to a boil and lower jars into boiling water using a holder, spacing them 2 inches apart. Pour in extra boiling water to cover jars by at least 1 inch. Bring water to a roaring boil, cover the pot, and process for 10 minutes.

Remove the jars from the stockpot and place onto a cloth-covered or wood surface, several inches apart, until cool, about 8 hours. Press the top of each lid with a finger, ensuring that the seal is tight (lid does not move up or down at all).