The source code of Sugar Activities is always at most one key-stroke away (Fn-space or Ctrl-Shift-V). It is also available from a submenu of an Activity's instance on the Sugar Frame.
The source code is displayed in an Alert window.
View Source: duplicate option for an activity
There is an option to duplicate an activity has been added to the View Source alert. By selecting this option, a copy of the activity is created in the user's $HOME/Activities directory. Thus we hope to encourage Sugar users to make modifications and improvements to the code they use without the risk of breaking the original activity.
View Source for sugar-toolkit
There is also an option to display the source code of the sugar-toolkit has been added to the View Source alert.