An example embodiment may involve receiving, from a client device, a request to access a web-based resource of a computational instance. One or more server devices disposed within the instance may be configured to be able to execute a plurality of program code units. A software application may be configured to identify one or more of the program code units that, since a previous software release for the instance or in a subsequent software release for the instance, have been modified or added, and store a corresponding change indication for each identified program code unit. The embodiment may also involve, as part of carrying out the request, executing a subset of the program code units, and may further involve generating and providing for display a representation of the web-based resource including a region specifying each of the subset of program code units for which there is a stored change indication.