On Windows, you will find the custom profiles in.
%appdata%\BambuStudio\user
There will be a default subfolder and one with a number, go into the whose name is a long number.
In the filament subfolder you find them in a .json format.
{
“filament_settings_id”: [
“Generic PLA - +10°C”
],
“from”: “User”,
“inherits”: “Generic PLA”,
“is_custom_defined”: “0”,
“name”: “Generic PLA - +10°C”,
“nozzle_temperature”: [
“230”
],
“nozzle_temperature_initial_layer”: [
“230”
],
“version”: “1.4.1.4”
}