According to the paper’s abstract,

- We’d like to study exoplanet atmospheres, but that’s hard because you can’t separate them from the star. Brown dwarfs are a good substitute because they are kind of like really big exoplanets.

- There’s chemistry happening inside the atmosphere of a brown dwarf, and chemicals will get transported up or down from where they are made. The detection of HCN in the brown dwarf spectrum means that some of our models for brown dwarfs are wrong.

You could try reading the linked paper. If I am reading it correctly, basically, we have atmospheric models for brown dwarfs and the presence of C2H2 and compounds cannot be explained by those models. So they think there are more complex atmospheric processes like aurora or lightning behind it.

They're inorganic compounds that can be produced without life.

The interesting part is that these are really weird chemicals to show up in a star. Acetylene isn't stable enough to just hang around for millions of years, so it must be being actively produced somehow. This brown dwarf is doing things we can't explain.

It's a neat find, but (almost certainly) not aliens.

One neat thing I know about HCN and early chemical evolution is that some DNA bases can be created from HCN polymerisation.

https://pubmed.ncbi.nlm.nih.gov/31491/

Like if you look at adenine, it is 'just' N-C-N-C all the way round.