  The Offline software framework for data analysis of the Pierre Auger
Observatory is a set of computational tools developed to cater to the needs of
a large and geographically dispersed collaboration established to measure the
spectrum, arrival directions, and composition of ultra-high energy cosmic rays
over a period of 20 years. One of its design goals was to facilitate the
collaborative effort by allowing collaborators to progressively contribute
small portions of code. The observatory has grown over time and it has
undergone improvements and additions that have tested the flexibility of the
framework. The framework was originally thought to accommodate a hybrid view of
cosmic ray detection, made of a surface and a fluorescence detector. Since
then, the framework has been extended to include a radio antenna array and both
under-ground and above-ground scintillator arrays. Different tools from the
framework have been used by other collaborations, notably NA61/Shine and HAWC.
All these experiences accumulated over the years allow us to draw conclusions
in terms of the successes and failures of the original design.
