| jbb | JobEditor32 Binary Job Data |
| jbc | Jetico BestCrypt Container |
| jbd | SigmaScan Data |
| jbeam | BeamNG.drive Vehicle Definition Format Data |
| jbf | Paint Shop Pro Browser Cache |
| jbi | Motoman Robot Job |
| jbk | Jot+ Notes Note Backup |
| jbk | Juno Client Software Backup |
| jbm | Jbmgen Data |
| jbt | JAWS Braille Tables Data |
| jbw | Scitor Project Scheduler Schedule Data |
| jbx | Music Ace 2 Jukebox Data |
| jbx | Project Scheduler JBX Data |
| jc | CelLab Compiled Rule |
| jc | FlashGet Partial Download |
| jc1 | FlashGet Partial Download |
| jcamp | JCAMP-DX Format Data |
| jcd | FlashGet Download Database |
| jceks | Java Cryptography Extension KeyStore |
| jch | CelLab Population History Log |
| jcl | JCloze Data |
| jcn | JobClock.NET TimeSummit Data |
| jcp | CelLab Pattern Data |
| jcp | Microsoft Exchange ESE Checkpoint File |
| jcrypt | JCrypt Data |
| jcsk | JetCast Skin Data |
| jcv | Garmin City Navigator Junction View |
| jcvib | Joy-Con Vibration Data |
| jcw | JCreator Workspace |
| jcw | JCross Data |
| jcx | JetAudio JetChat Data |
| jd | Doclava Javadoc Template |
| jd | JDownloader Data |
| jd | Jigsaw Terminal Data |
| jda | Winphone Fax Send Journal Data |
