Impostor wrote: ↑Fri Jan 26, 2024 1:11 pm
Better to grab newer versions from for example github or kx.studio imo.
Even kx.studio is frequently quite a bit behind, in my experience. I'll generally go directly to the plugin's own website, if possible. (For reference, current release of LSP is 1.2.14. Kx.studio has 1.2.12. Ubuntu 23.10 is on 1.2.11. I have no idea what Mint is at.)
As for the actual question, like Impostor suggested, dummy packages, if I'm not mistaken, are typically placeholders that are mostly there for backwards compatibility when for example the name of a package has changed. They probably simply redirect to installing the actual current package. I'm not a Mint user and I don't know what the package breakdown for LSP stuff is on Mint, so I can't say which one of them you need to install. (If there's an lv2 package that's not a dummy, you might just install that. Otherwise it might be that all the plugin formats are contained in a single package...)