"10 maps on the disc
Only two are unreleased (Camp and Skyscraper)
33 unreleased weapons on the disc in some form
Some weapons have complete descriptors (and may or may not be actually complete)
Others which have incomplete descriptors (and may or may not be actually complete)
Weapons list:

Sploosh-o-matic – Squid Beakons & Killer Wail
Neo Sploosh-o-matic – Point Sensor & Kraken
Neo Splash-o-matic – Burst Bombs & Inkzooka
N-ZAP ’89 – Sprinkler & Inkstrikes
Custom Dual Squelcher – Squid Beakon & Killer Wail
Luna Blaster – Ink Mines & Inkzooka
Luna Blaster Neo – Splat Bombs & Bomb Rush
Range Blaster – Splash Wall & Inkstrike
Custom Range Blaster – Splat Bombs & Kraken
Rapid Blaster Pro – Seekers & Inkzooka
Rapid Blaster Pro Deco – Disruptors & Killer Wail
L-3 Nozzlenose D – Burst Bombs & Kraken
H-3 Nozzlenose – Suction Bombs & Echolocator
H-3 Nozzlenose D – Point Sensor & Inkzooka
Carbon Roller – Burst Bombs & Inkzooka
Carbon Roller Deco – Seekers & Bomb Rush
Inkbrush Nouveau – Ink Mines & Bubbler
Octobrush – Squid Beakons & Kraken
Octobrush Nouveau – Splat Bombs & Inkzooka
Bloblobber
T_BigBall_Strong01
Triple Bloblobber
T_BigBall_Diffusion01
Bomlobber
T_BigBall_Launcher01
E-liter 3K Scope
Custom E-liter 3K Scope
Bamboozler 14 Mk I
Bamboozler 14 Mk II
T_Gatling_Standard00
T_Gatling_Standard01
T_Gatling_Hyper00
T_Gatling_Hyper01
Other details:

There are also Ranked mode game type selection images
These are Splat Zones, Tower Control, Rainmaker
All of the text for Rainmaker is already on the disc, but the leaker isn’t revealing it yet."

Remember there is an update in august, I wouldn't be surprised if they add more maps along with that