Same question. Looking at the history of the file, it's being quite used. Moreover, I've run a script to gather similar questionable items and it seems there are more places like that. First is the number from /start/..., the second is the number of occurrences:

222467 => 10
217186 => 7
213337 => 7
224285 => 6
200140 => 4
242234 => 3
209945 => 3
255058 => 2
243177 => 2
244792 => 2
240548 => 2
231245 => 2
219570 => 2
219923 => 2
202886 => 2
214124 => 2
211552 => 2
218608 => 2
225738 => 2
225029 => 2
210939 => 2
214696 => 2
213259 => 2
210152 => 2
208351 => 2
207498 => 2
208861 => 2

I've looked over how everything works. And there are duplicate mods or different mods which use the same file. But after looking at the commit history, it looks like some of those download IDs get used as a placeholder, I'm guessing. So might explain some of the duplicates. Some might be accidental tho, I have a feeling that the file is manually managed

Yes this is intentional: patching shit mods / broken mods / with unharmful and small addons to preserve the addons numbering.