I think it was said somewhere that Rios made modifications to the ship, so maybe in the alternate whatever it just looks like proper Starfleet ship (without the wings and normal nacelles). Maybe on the outside it just looks like an XL runabout lol.
One of the set designers said the ship wasn't Federation, but was refitted with Federation technology. While I don't believe the Eaglemoss booklet gives a straight origin for the ship from any of the info.
We know the shipyards where she was built and that it must have been over a hundred years before the beginning of Picard, but we don't have any more detail about who built or owned her and if at any point she was connected to Starfleet. (Though of course, what the designers told Eaglemoss is only beta canon, so who knows whether the writers will stick to that if it ever comes up) I would imagine if Sirena is part of whatever fun house mirror version of Starfleet they stumble into in season 2, it'll be more like a requisitioned or commandeered private vessel, not one that was purpose built for "Starfleet", but I guess we'll have to wait and see.
And just like that, La Araña Cosmica La Sirena's thread is alive again! Pursued by totalitarian Federation ? Suspected La Sirena would drop the civilian Frankenstrat colors for this reality, and is now a more neutral Starfleet gray. (without the sporty colors does look more military(or a soupedup aggressive runabout)) What ships is blasting La Sirena here? And La Sirena blasting here? And it appears they are using the ol' sun's gravity slingshot warp trick to pull them through time...
La Sirena's a memorable Trek civilian ship. Maybe that wouldn't mean much, but Book's ship over at Star Trek Discovery is completely forgettable despite presumably being much more advanced. Like Dr. Who's TARDIS, Book's ship is mostly left to the imagination except for the main bridge/control room, and that room itself isn't very remarkable.
I dunno I like the weird shape of Book's ship and it's transforming ability. The TARDIS is iconic, and there's not a single other ship in that show which comes within a million miles. Bad comparison.
the 6th and 7th gifs. The ship chasing the Vulcan ship in the first gif and in the second gif, the two ships on the left.
I'm talking about these gifs, I miscounted. The ship chasing the Vulcan ship here: And the two ships on the left here:
The problem with Book's Ship is that the show runners haven't given it a official name. It's still known as "Book's Ship".
I thought about asking the same question, but then I realized I'm not a ship person and therefore unqualified to comment on Trek ships...for reasons.