Is it? Across Ubuntu, RHEL, and Archlinux, basically every package is being built against different versions of its underlying dependencies, and is being patched as needed to work with those distros. Trademarks weaken with lax enforcement, so you'd think if that interpretation held it would be amazingly dangerous for any trademark holder whose software was being packaged for Linux distros.
I suppose the closest analogy I can imagine from non-malicious(arguably) history would be software hosting sites that would repackage installers with their own adware or toolbar or whatever "value add".
By using the brand on something else, the reputation can be damaged
https://bazaar.launchpad.net/~mozillateam/firefox/firefox.ja... is the config for what becomes Ubuntu's firefox package
https://gitlab.archlinux.org/archlinux/packaging/packages/fi... is the equivalent for Arch
Both apply different configurations, use different versions of dependencies, and in Arch's case applies a patch to the upstream code.
Which of them isn't Firefox?
They had distribution networks, authorized to carry their brand.
But there were also “gray market” distributors, that would do things like resell foreign market gear, or devices that were separated from sales promotion bundles.
These were our brand, but the company would not support them. No hardware fixes (unless paid), no firmware upgrades, and no marketing support.
Often, the savings were minimal. It was expensive gear; even at a discount.