Using the Resource Pack Generator in Vanilla
Starting in Minecraft 1.21, music discs are now data-driven, which means you can now add records with custom songs to your world without any mods at all!
As a result, the packs generated via the Fox Nap Resource Pack Generator don't actually need the mod to be used in your world! Simply put the generated datapack (default name: FoxNapDP.zip) into your world's datapacks folder, the resource pack (default name: FoxNapRP.zip) into your instance's resourcepacks folder, and you'll be able to give yourself custom items in your world that will play your songs in a jukebox (you can see an example of that behavior here).
Note that the generated datapacks do not currently provide any way to obtain such items in survival, but the command for doing so is structured as follows:
give @s minecraft:golden_apple[jukebox_playable={song:"foxnap:track_1"}]Note further that, in this example, the item you receive isn't a music disc, but it will still play in a jukebox, as shown below:
