I think you might be asking about the 'Asset Tracking Toggle.' I don't know of another "Asset Manager" in Max. But if Asset Tracking shows a "file missing," just go to Slate Material Editor, open the 'Scene Materials', right click on the header name and choose 'Show Subtree' and you'll see the material with the bitmap nested below it. That's the material it's connected to.
I don't know that Asset Tracker has ever had the ability to show you what material it's 'missing' from. It would be a nice feature. Maybe head over to the "Ideas" forum and post that there. If it gets votes, it might get implemented.
FYI, if you frequently have missing bitmaps and it's difficult and frustrating to reconnect them all, I'd suggest you look at a plugin called 'Relink Bitmaps.' Colin Senner makes it and is a nice guy. It will save your life, is not very expensive and has been around a long time. It's coding is solid and reliable and it's one of the 3rd party Max plugins I could not live without. I tell him every year when Max is released, "please, please don't stop making this..."...lol... 🙂
Rob Holmes

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3ds Max (2023-2026), V-Ray 7, Ryzen 9 9950X3D Processor, DDR5 128MB, Gigabyte Aorus X870E Master motherboard, Sabrent Rocket NVMe Gen5 M.2 drives, NVidia RTX 4090, Space Pilot Pro, Windows 11 Pro x64, Tri-Monitor, Cintiq 13HD, Windows 11 x64
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