The most common and most likely answer to this crossword clue is the 5 letter word SQUIB
I've seen this crossword clue in Financial Times
S
Q
U
I
B
More clues leading to the result SQUIB
- Gourmets quibble, eating banger
- Firework son left briefly on top of bonfire
- Incomplete grill in chassis of superb little banger
- Pyrotechnicians quibble about it
- Firework: possibly 25 are missing, one British
- Small weak person liable to get lit up
- Lampoon francophone who resides in centre of Lisbon
- Son almost dropped second-rate firework
- Second pound daughter wasted getting second-class firework
- Couple of quagmires disrupting relative’s firework
Buddy explains!

The straight part
We know that "Pyrotechnicians quibble about it" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case pyrotechnicians quibble about it = squib.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SQUIB mean?
SQUIB noun- A small firework that is intended to spew sparks rather than explode.
- A similar device used to ignite an explosive or launch a rocket, etc.
- A kind of slow match or safety fuse.
- Any small firecracker sold to the general public, usually in special clusters designed to explode in series after a single master fuse is lit.
- A malfunction in which the fired projectile does not have enough force behind it to exit the barrel, and thus becomes stuck.
- The heating element used to set off the sodium azide pellets in a vehicle's airbag.
- In special effects, a small explosive used to replicate a bullet hitting a surface.
- A short piece of witty writing; a lampoon.
- A writer of lampoons.
- In a legal casebook, a short summary of a legal action placed between more extensively quoted cases.
- A short article, often published in journals, that introduces theoretically problematic empirical data or discusses an overlooked theoretical problem. In contrast to a typical article, a squib need not answer the questions that it poses.
- An unimportant, paltry, or mean-spirited person or thing.
- A sketched concept or visual solution, usually very quick and not too detailed.
- To make a sound like a small explosion.
- To throw squibs; to utter sarcastic or severe reflections; to contend in petty dispute.