Any idea why the url is blank for curseforge mods in the .index/mod.toml?

[EchoEllet]

When I try to download any mod using the launcher, it will create some metadata that has the same underline data as some other launchers, when installing any mod from CurseForge, it will always have blank URL field:

filename = 'moredragoneggs-4.0.jar'
name = 'More Dragon Eggs'
side = 'both'

[download]
hash = '22122de407d0df09a0f36c580ed56c22faa52551'
hash-format = 'sha1'
mode = 'metadata:curseforge'
url = ''

[update.curseforge]
file-id = 4670879
project-id = 358700

When downloading and installing mods from Modrinth mod provider it will have a valid download URL:

filename = 'architectury-9.2.14-forge.jar'
name = 'Architectury API'
side = 'both'

[download]
hash = 'cf67f2050cafa00f0bee42e6d7bef77fdb808ac4f71742f7b4d6d5c1e6ffb49561a5a252f332d2b78a9767bdb5faa284611790dba303fbdc736ae36d794f61c7'
hash-format = 'sha512'
mode = 'url'
url = 'https://cdn.modrinth.com/data/lhGA9TYQ/versions/1MKTLiiG/architectury-9.2.14-forge.jar'

[update.modrinth]
mod-id = 'lhGA9TYQ'
version = '1MKTLiiG'

The reason I'm interested in this field because I'm creating a script for syncing the Minecraft content instance to all players from one player and I decided to use the MultiMc mods metadata and migrate all the data to the script in a single command, I would like to know more about when the URL is blank so I handle this correctly

Thank you.

[Trial97]

We do not store the download url for curseforge mods.
For modrith we use that in the mrpack export.

[EchoEllet]

We do not store the download url for curseforge mods.
For modrith we use that in the mrpack export.

Thank you. It looks like the only way is to get the download url by the info in the toml file like the project id and version using CurseForge api

[DioEgizio]

yeah trial didn't explain much but because of cf's ToS we can't store download URLs of curseforge

[EchoEllet]

yeah trial didn't explain much but because of cf's ToS we can't store download URLs of curseforge

Is that the same case for PolyMc or MultiMC and other launchers? I'm still not sure how all these launchers if they use the exact same mods metadata or if they store them differently and share some common data

[DioEgizio]

PolyMC doesn't store cf URLs as they haven't changed almost anything after the hostile takeover, MMC doesn't even support curseforge anymore. No launcher stores curseforge URLs anymore, packwiz had to change spec to accomodate this requirement. Modrinth used to allow curseforge cdn links until they asked them to stop, see https://blog.modrinth.com/p/modpack-changes