Yes, this is normal. Setting Firefox as the default browser just makes it the default for .htm and .html files, and for the HTTP and HTTPS protocols.
It does NOT make it the default for any other file types, even if it can open them. You can set the default yourself, but if not then Edge is the Default for most of them. The file type defaults not set by choosing Firefox as your default browser include .pdf and, as you have found, .xml.
Personally I find that Edge does a better job of rendering a .xml file, in particular the comments, so I leave it as the default.
For .pdf I prefer Firefox as the default.
1366x768 native resolution, up to 2560x1440 with Radeon Virtual Super Resolution
Hard Drives
1TB Samsung EVO 870 SSD
Internet Speed
50 Mbps
Browser
Edge, Firefox
Antivirus
Defender
Other Info
fully 'Windows 11 ready' laptop. Windows 10 C: partition migrated from my old unsupported 'main machine' then upgraded to 11. A test migration ran Insider builds for 2 months. When 11 was released on 5th October 2021 it was re-imaged back to 10 and was offered the upgrade in Windows Update on 20th October. Windows Update offered the 22H2 Feature Update on 20th September 2022. It got the 23H2 Feature Update on 4th November 2023 through Windows Update, and 24H2 on 3rd October 2024 through Windows Update by setting the Target Release Version for 24H2.
My SYSTEM THREE is a Dell Latitude 5410, i7-10610U, 32GB RAM, 512GB NVMe ssd, supported device running Windows 11 Pro.
My SYSTEM FOUR is a 2-in-1 convertible Lenovo Yoga 11e 20DA, Celeron N2930, 8GB RAM, 256GB ssd. Unsupported device: currently running Win10 Pro, plus Win11 Pro RTM and Insider Dev, Beta, and RP 24H2 as native boot vhdx.
My SYSTEM FIVE is a Dell Latitude 3190 2-in-1, Pentium Silver N5030, 8GB RAM, 512GB NVMe ssd, supported device running Windows 11 Pro, plus Insider Beta, Dev, and Canary builds (and a few others) as a native boot .vhdx.
My SYSTEM SIX is a Dell Latitude 5550, Core Ultra 7 165H, 64GB RAM, 1TB NVMe SSD, supported device, Windows 11 Pro 24H2, Hyper-V host machine.
Operating System
Windows 11 Pro
Computer type
Laptop
Manufacturer/Model
Dell Latitude E4310
CPU
Intel® Core™ i5-520M
Motherboard
0T6M8G
Memory
8GB
Graphics card(s)
(integrated graphics) Intel HD Graphics
Screen Resolution
1366x768
Hard Drives
500GB Crucial MX500 SSD
Browser
Firefox, Edge
Antivirus
Defender
Other Info
unsupported machine: Legacy bios, MBR, TPM 1.2, upgraded from W10 to W11 using W10/W11 hybrid install media workaround. In-place upgrade to 22H2 using ISO and a workaround. Feature Update to 23H2 by manually installing the Enablement Package. In-place upgrade to 24H2 using hybrid 23H2/24H2 install media. Also running Insider Beta, Dev, and Canary builds as a native boot .vhdx.
My SYSTEM THREE is a Dell Latitude 5410, i7-10610U, 32GB RAM, 512GB NVMe ssd, supported device running Windows 11 Pro.
My SYSTEM FOUR is a 2-in-1 convertible Lenovo Yoga 11e 20DA, Celeron N2930, 8GB RAM, 256GB ssd. Unsupported device: currently running Win10 Pro, plus Win11 Pro RTM and Insider Dev, Beta, and RP 24H2 as native boot vhdx.
My SYSTEM FIVE is a Dell Latitude 3190 2-in-1, Pentium Silver N5030, 8GB RAM, 512GB NVMe ssd, supported device running Windows 11 Pro, plus Insider Beta, Dev, and Canary builds (and a few others) as a native boot .vhdx.
My SYSTEM SIX is a Dell Latitude 5550, Core Ultra 7 165H, 64GB RAM, 1TB NVMe SSD, supported device, Windows 11 Pro 24H2, Hyper-V host machine.
