A fox with a surprisingly useful job
A pangram is a sentence or phrase that uses every letter of an alphabet at least once. For the English alphabet, that means all 26 letters. Merriam-Webster gives this definition.
Meet the famous example: “The quick brown fox jumps over the lazy dog.” It sounds like a wildlife report from someone with very little happening that afternoon. Yet the fox is doing more than annoying a dog.
Where are the awkward letters?
Look for the letters you might otherwise leave out. There is a q in quick, an x in fox and a z in lazy. The less conspicuous letters are there too.
Ignore spaces and the full stop: the sentence has 35 letters, but 26 different letters. That is allowed. A pangram needs to include the alphabet; it does not have to use each letter only once.
Why does it keep turning up on screens?
A pangram gives you a compact sample of the whole alphabet. That makes it handy for trying a typeface: you can see how its letters look inside words rather than in an A-to-Z parade.
Wordsmith also describes using pangrams for typing practice. One short sentence makes you reach for every alphabetic key. The fox has found steady work.
One tiny edit breaks the trick
Change jumps to jump. Which letter disappears from the sentence?
S. There is no other s to cover for it, so the edited sentence is no longer a pangram. Keeping the story almost unchanged is not enough; the letter rule decides.
This is a different challenge from an anagram, which rearranges an existing set of letters. Try writing your own pangram: start with a sensible sentence, then hunt for the letters still missing. The rare ones tend to demand the strangest guests.