To use Arduino Web Editor on a Raspberry Pi, the Arduino Create Agent must be built from source code. It is not very difficult but does assume familiarity with Linux command line mode.
This should work on other Raspberry Pi's but but has only been tested on a Pi 4 running buster.
$ sudo apt update
$ sudo apt upgrade
If the upgrade step, says to reboot, please do so. Then continue with the next step. Cut and paste the next step because it is too long to enter by hand.
$ sudo apt install golang libappindicator1 libappindicator3-0.1-cil \
libappindicator3-0.1-cil-dev libappindicator3-1 libappindicator3-dev \
libgtk-3-0 libgtk-3-dev
$ cd $HOME
$ go get github.com/arduino/arduino-create-agent
$ export GOPATH=$(go env GOPATH)
$ export PATH=$PATH:$(go env GOPATH)/bin
$ cd $GOPATH/src/github.com/arduino/arduino-create-agent
$ go build
$ cp config.ini $GOPATH/bin
The previous steps should only be done once to build the Create Agent. The file is left in /home/pi/go/bin/.
To launch the Create Agent just run from command line.
$ ~/go/bin/arduino-create-agent &
The Arduino icon should appear in the GUI tray (top right of screen). Click on the icon then click on the "Go to Arduino Create" option to open a browser window at https://create.arduino.cc.
To automatically start the Create Agent without a command line window try the following.
$ mkdir /home/pi/.config/autostart
$ cat >/home/pi/.config/autostart/arduino-create-agent.desktop <<EOF
[Desktop Entry]
Type=Application
Name=arduino-create-agent
Comment=
Exec=/home/pi/go/bin/arduino-create-agent
Terminal=false
EOF
At this point, reboot the Pi (or logout then login). The Arduino Create Agent should be running.