How does seed finding work? I was curious as to how these 2 seeds are practically the same (-4530634556500121041 and -978983300365063633). Could someone please help me understand?

Ask in the discord.

Is it a secret information?

well we have a discord channel for this but basically, people use computers to find 12 eyes then they filter them (again using computers) to make the list be for example only plains villages or only villages with close ruined portals that stuff was done in this case by funkyface (edit: as silliest said bellow majority of the credit for seed searching should go to Kaptain Wutax and especially Mathew). People then go through the seeds individually to check for 20 obi chests or enough obi to complete a ruined portal and make an exit portal that is how -978983300365063633 was found then you can use its structure seed to find in its case 300 more seeds that are similar but not the exact same then people go through those individually to find the best one in this case -4530634556500121041 (I think people are done searching the sisters but maybe not)

as to how they are practically the same seed its that they are sister seeds or that they share the same structure seed basically each mc seed can have some (most do) other seeds that are very similar to them usually the structures aren't identical but they are similar and sometimes the exact same as for the nether I think they can have different nethers but this one doesnt seem to. if you want a few more examples of sister seeds here are a few that are sisters to the seeds you mentioned 8712481622759533103 2606726427951983151 -8527860700768146897 639216340744497711 -3957551503917225425 I hope that explains it but tbh after searching through hundreds of sisters I still have no idea how they work

@Spike_Brownie, thanks, that helps a lot, how do you get the seed finder?

If your talking about looking for 12 eyes Matthew has some tutorials on it (idk where you would find those.) but there are programs to find say a village with a ruined portal in it or a swamp hut in a ruined portal in a village or something like that SASSA (you can just look up SASSA seed tool) is the major one that I have seen, mango has a video on how to use that. But really if I were you I would ask about it on the seed-finding channel on the discord.

ok thanks

just want to offer the right credit: matthew and kap helped with searching 12 eyes the most, funky face filtereed them and made a list, and a bunch of others manually searched the seeds aswell. i persoanlly think most of the credit should go to matthew when it comes to finding 12 eye seeds. he contributed to the project the most