| pkc | Jython JAR Cache |
| pkcs12 | PKCS #12 Data File |
| pkcs7 | PKCS #7 Certificate Data |
| pkd | Eurotherm Encrypted Hydra History Data |
| pkf | Adobe Audition Peak File |
| pkgx | Microsoft UE-V PKGX Data |
| pki | LibVirt PKI Data |
| pkj | PokerJuice Data |
| pkk | PuTTY Private Key |
| pkl | Migration Wizard Packing List File |
| pkn | Microsoft SMS Package Creation Notification |
| pkr | PGP Public Keyring File |
| pks | STOE Powder Diffraction Peak Data |
| pkt | Cisco Packet Tracer Network Simulation Model |
| pku | FidoNet Batched Newsgroup Data |
| pkw | CabnetWare Package |
| pky | PockeTTY Security Certificate |
| pl3 | Harvard Graphics ChartXL Palette Data |
| pl3 | Pathloss Link Design Data |
| pl4 | Micrografx Designer 4.0 Palette |
| pl4 | Pathloss Link Design Data |
| pl5 | Pathloss Link Design Data |
| plb | Microsoft Robotics Developer Studio Playback Data |
| ple | Messenger Plus! Live Encrypted Log |
| plg | Microsoft Developer Studio Build Log |
| plgx | KeePass v2 Plugin |
| plib | SAM Old Dirichlet Mixture Prior Library |
| plj | Plus 2D Job Data |
| plk | Password Safe Lock File |
| plma | Protomata-Learner PLMA Data |
| plmn | GSM Public Land Mobile Network Data |
| plmx | PDXpert PLM XML Data |
| plmxml | Siemens PLM XML Data |
| plo | Radio Toolbox Playlist |
| plot | Matplotlib Plot |