I want to edit a widget and give option of 'onChange Microflow' similarly as other widget consist of. How it is possible to edit/customize widget for my project? Also, I want to remove a popup showing up on validations from widget 'customInputMask' as I just need the validation feedback nothing extra. How this is possible?
A widget .mpk file can be extracted as a zip. Rename to .zip and extract the package. You can then inspect the code and change it to your liking. Repack it again and place it again in the widget directory. See also the documentation here: https://docs.mendix.com/howto/custom-widget-development/