https://www.epo.org/en/node/notification-sequence-listings-belonging-4

The communication under Rule 71(3) EPC contains a sequence listing with the extension .app. Is this legally valid and how can I view the sequence listing?

The .app file extension is valid for sequence listing files recognised in Annex F to the Administrative Instructions as in force until 30 June 2022. Files with an .app extension are simple text files that can be read with Notepad, MS Word or any other text editor/viewer able to open TXT files. If a file has an .app extension, it is the sequence listing file the EPO downloaded from WIPO's PATENTSCOPE on entry into the European phase. The EPO uses these sequence listing files for the formal standard-compliance check, search and examination. It is considered the sequence listing as published with the international application and, therefore, as part of the Druckexemplar together with the communication under Rule 71(3) EPC.