I have downloaded KDevelop 5 from https://www.kdevelop.org/download
wget -O KDevelop.AppImage
http://download.kde.org/stable/kdevelop/5.0.3/bin/linux/KDevelop-5.0.3-x86_64.AppImage
chmod +x KDevelop.AppImage
./KDevelop.AppImage
Now, I want to remove it, how can i do that? Thank you.
The KDevelop AppImage is just a standalone executable.
In order to remove it you can simply remove the downloaded file:
rm KDevelop.AppImage