I tried downloading gcc-5 from unstable on my EV3 brick, I connected the brick to the internet using an Ethernet adaptor

gcc-5 should have installed without any issues.

What actually happened

I got the following messages:
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package gcc-5

Desktop (please complete the following information):

• OS and version: Windows 11 pro version 22H2
• Connection Type: Ethernet adaptor
• Software: PuTTY

Robot (please complete the following information):

• Device: EV3
• Versions: Kernel: 4.14.117-ev3dev-2.3.5-ev3