/usr/share/kservices5/pop3.protocol is in kf5-kdepimlibs-kio-plugins 4:16.04.2-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | [Protocol]
exec=kf5/kio/pop3
protocol=pop3
Capabilities=SASL
input=none
output=filesystem
listing=Name,Type,Size
reading=true
writing=false
deleting=true
source=true
makedir=false
linking=false
moving=false
X-DocPath=kioslave5/pop3/index.html
Icon=mail-folder-inbox
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