Yeah, the original Game Boy Advance doesn’t actually have a charging port on it in the first place!
Unlike the Game Boys that came before it, the Game Boy Advance didn’t have a barrel connector on it to connect an AC adapter for powering it without batteries. Due to that, Nintendo made an accessory¹²³ for the Game Boy Advance that plugged into the battery compartment (which completely replaced the battery cover). It had a proprietary port on it which you would use to plug in an AC adapter that would then plug into a wall outlet and power (not charge) the Game Boy Advance. I believe that may be what the parent poster was referring to.
Unlike the Game Boys that came before it, the Game Boy Advance didn’t have a barrel connector on it to connect an AC adapter for powering it without batteries. Due to that, Nintendo made an accessory¹²³ for the Game Boy Advance that plugged into the battery compartment (which completely replaced the battery cover). It had a proprietary port on it which you would use to plug in an AC adapter that would then plug into a wall outlet and power (not charge) the Game Boy Advance. I believe that may be what the parent poster was referring to.
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¹ — https://www.nintendo.com/consumer/systems/gameboyadvance/hoo...
² — https://www.amazon.com/dp/B00005B8G0
³ — http://ign.com/articles/2001/09/30/game-boy-advance-ac-adapt...