The logo tag is currently used by a grand total of three questions:
A no-background favicon for my website?
Windows 8.1 start-up logo replaced with ASUS logo after BIOS update
How to change the BIOS splash screen on HP Pavilion G4 1303AU?
There's no obvious real commonality between these questions (except, perhaps, the fact that the latter two both deal with BIOS in some way). The tag has no tag wiki to provide guidance. I honestly cannot imagine a question that would be on topic for Super User and which could properly be tagged with only "logo" in the sense of graphical logotype.
When a tag means so many things in different contexts, either that tag must be renamed to something more specific, or just plainly removed. BIOS logo questions should be in the BIOS tag, boot logo should be in the boot/bootloader tag. Is not necessary to have several tags to go to the specific like an index.