Sailor's Cross Knot', adding a small 1/8" x 2" firesteel to the vertical section of the cross is easy to do. For this project I made a Sailor's Cross Knot lanyard/fob/zipper pull, with swivel clip for attachment, jute cord inside the paracord, and a removable/replaceable firesteel in the vertical section of the cross, shown with a Wenger Evogrip 18 Swiss Army Knife. I ended up using less than 5 feet of paracord, and double that length of jute twine(Thanks for the roll of twine, Manny!). An Arms-Akimbo knot was tied with the single strand coming out the bottom of the cross.
I first replaced the paracord's inner strands with jute cord, which can be pulled apart and made into a nest to use as tinder to catch a spark from a firesteel or flint. From that you get a flame that you use to get kindling burning, then add in larger bits of sticks, branches, and logs for a sustainable fire.
I'd seen a video, done by fellow knot tying friend Ken earlier this year, showing some wax/paraffin treated jute twine being pulled from a wet section of paracord and lit with sparks from a firesteel. I didn't give the jute for this project a wax coating, but it's certainly a useful idea, giving the jute a longer burning time like a candle wick, to help in getting a fire started.
Jute has been made for centuries, and paracord has been around 70+ years, so their uses in knot work are as old as they are, but the internet has plenty of search results to explore for more recent combinations of the two, like this example from 'The Paracordist'.
If you don't have a lighter or matches, learning primitive fire making
and survival techniques can help you use a firesteel to get a fire
going. There are literally millions of hits Googling those topics, so
if you get sidetracked, have fun but don't get burned. Fire can be
dangerous, so be safe with it.