| aproj | Leapfrog Geo Project |
| apz | Autoplay Media Studio Exported Project |
| argo | ArgoUML Project |
| arh | Siemens ProTool Compressed Project |
| art42 | Bernina Explorations v1.x Project |
| art50 | Bernina Embroidery Software v5.0 Design |
| art60 | Bernina Embroidery Software v6.0 Design |
| artproj | Artifacts Project |
| artx | Artisteer Project |
| as2proj | FlashDevelop Project |
| as3proj | FlashDevelop Project |
| ashprj | Ashampoo Burning Studio Project |
| asmproj | Atmel Studio Assembler Project |
| asproj | Visual Studio Analysis Services Project |
| asta | Astah Project |
| astah | Astah Project |
| asw | ACDSee Slideshow Wizard Project |
| ata | Antenna Web Design Studio Project |
| atgcproj | Genetyx ATGC Project |
| ato | ATO Modeler Project |
| atp | Visual Studio ACT Project |
| atpz | Automise Compressed Project |
| atsuo | Atmel Studio Project |
| atz3 | Automise 3 Project |
| atz4 | Automise 4 Project |
| aup | Audacity Project |
| aurx | AutoREALM Project |
| autoplay | AutoPlay Media Studio Project |
| avenirproj | StoryMill Project |
| avp | Avid Media Composer Project |
