Linux x64 AppImage download (v2.1.6) delivers corrupt/invalid file - wrong magic bytes?

[lunitrixx]

Environment

Key	Value
EchoAPI Version	2.1.6
Download URL	https://open.echoapi.com/open/dl/?client=LinuxAppImage&arch=x64
OS	NixOS 25.11 (x86_64-linux)

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Describe the bug

The Linux x64 AppImage downloaded from the official download endpoint cannot be executed. Inspection of the file reveals that it does not have valid AppImage or ELF magic bytes. This appears to be a server-side issue with the download, not a NixOS-specific problem - my Linux system would reject this file.

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Steps to reproduce

# Download the AppImage
curl -L "https://open.echoapi.com/open/dl/?client=LinuxAppImage&arch=x64" \
  -o EchoAPI_linux_x64_2.1.6.AppImage
chmod +x EchoAPI_linux_x64_2.1.6.AppImage

# Inspect magic bytes
head -c 4 EchoAPI_linux_x64_2.1.6.AppImage | od -t x1
# Output:
# 0000000 ec d0 2e 4d
# 0000004

# Attempt to run via appimage-run (NixOS)
appimage-run ./EchoAPI_linux_x64_2.1.6.AppImage
# readelf: Error: Not an ELF file - it has the wrong magic bytes at the start
# readelf: Error: Not an ELF file - it has the wrong magic bytes at the start
# Not an AppImage file

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Actual behavior

The downloaded file starts with ec d0 2e 4d - which i think is not a valid ELF or AppImage header.

All execution attempts fail:

• appimage-run → "Not an AppImage file"
• Direct execution → fails due to wrong magic bytes
• steam-run → tries to interpret the binary as a shell script, encounters syntax errors from raw binary data

The file appears to be corrupted, or the wrong file type.