There are three large scale weapon systems on the ship.
First are the conventional ones. There are sixteen massive railguns, arranged into four banks of four, intented for long-range anti capital ship combat, firing solid projectiles at extreme ranges. At short ranges they're capable of absolutely shredding smaller ships, but the relatively limited rate of fire makes them somewhat ineffective at this role. They're made for firing huge broadsides at big targets at long to extreme range, scoring occasional hits and whittling down the target. These magazines are full, being essentially energy weapons with thousands of rounds stored for each gun. Still, railgun projectiles the size of a person are serious business.
In addition, there are four great siege guns. These are not really capable of much traverse, and are intended to fire massive bombs of various types at slow speed, intended for saturation strikes. Traditional tactics is to get light-minutes or hours away from the target, and launch dozens or hundreds of these, flying with the bombs while launching more bombs, to launch a saturation attack. These magazines are empty, which makes sense. Can't really mothball something with warheads that need constant power to stay stable. A quick glance at the computer systems shows full schematics for a wide range of bombs, most of which are unfamiliar to you. Siege guns are immensely powerful, but firing them is like lighting millions of credits on fire. Make sure whatever you use them against is worth it.
Third is the primary energy weapon. This is not the standard monster-sized pulsed X-ray laser. This is what used to be termed a 'fracture cannon', or an extreme energy particle beam. This particular one also has 'fracture mode', where it fires a beam of high-speed ionized plasma, intended to splash against a shielded target, followed by a high-energy particle beam, intending to create exotic particle showers.
In other words, you have a high-end particle beam, great for making enemy hulls into useless radioactive messes, with the fracture mode intended to force exotic materials through even the best shields. You can't really protect against photons of every power level from gamma on down, and a massive shower of exotic particles, all at the same time. Something will get through and damage will be done.
For smaller ships, there is the standard range of missiles, anti-missiles, laser turrets, and what could best be termed 'saturation fire fragmentation cannons', short ranged weapons with slow-refire rates intending to turn an entire flank of the ship into a temporary 'no go zone' filled with sheets of fire and explosive shells. All standard and used to this day.
Next stop is the hangar bay and engines. Which is generous. The hangar bay can take in a dozen standard containers, end-to end, and has full fittings for refueling, rearming, and reconfiguring all kinds of small and medium craft. Most of what you would normally consider 'large craft' could fit in there as well. Cranes, tools, and a secondary machine room loaded to the gills with spares lie before you.
The big problem with fitting a 'large' ship in here is that the bay is already full. Forty-eight old Imperial fighters are here, of the skyripper beam weapon design. There are also twenty four old imperial bombers, and eighteen 'protectors', or shield deployment ships, enough to cover entire wings of fighters or bombers in high-end protective shielding dozens of kilometers out. Enough to put up two layers of additional shields around this ship as well, if turned to that use..
The other half of the hanger is full of support craft. Six mining ships, two salvagers about the size of your own, but fitted with real equipment, not the cobbled-together modern replacements. Four gas harvesters, a single refinery craft, two repair and construction ships, and two tugs, small vessels with oversized jump drives and real tractor emitters.
Your next stop are the engines. As expected, the ship is powered by three of the ancient, skyscraper-sized standard Grand Fleet engines, many of which are currently used around the galaxy as generators for stations or cities. But these are the better ones, the mark fives. More power, more reliability, and much, much easier maintenance. The old mark fours required dozens of crew to keep running properly, or significant amounts of downtime. But these new ones use the same structural projection technology to make the active sections far more accessible, and the robots and waldos to keep things running can work even when it's hot, cutting maintenance requirements roughly in half. The extra power is never unwanted either.. an old cruiser used to be strained pretty good in a hot battle with everything running. With these babies it can run cool even when running hot, making a catastropic breakdown less likely and providing more spare capacity for upgrades or combat damage.
(to be continued. Yes, the ship-porn will stop after this one set of descriptions.)