Prompt says "Debian", not "Ubuntu"

This is a cosmetic bug. The minimal way to reproduce it (from my limited testing) seems to be attempting an install of 16.04 in UEFI mode with a partitioned drive but no ESP. This causes a "Force UEFI installation?" prompt to appear, which says:

This machine's firmware has started the installer in UEFI mode but it looks like there may be existing operating systems already installed using "BIOS compatibility mode". If you continue to install Debian in UEFI mode...

Presumably that should be Ubuntu, not Debian.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubiquity 2.21.63
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
CasperVersion: 1.376
Date: Fri Apr 29 20:07:25 2016
ExecutablePath: /usr/lib/ubiquity/bin/ubiquity
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash ---
InterpreterPath: /usr/bin/python3.5
LiveMediaBuild: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)