apt pinning: find out from which system version is a package

[Emanuel Berg <moasenwood@zoho.eu>]

With apt pinning [1], in /etc/apt/preferences ,
I have learned that one can have certain packs
from another release than the rest of the
system, seemlessly (?) with apt-get and the
other tools, for example like this for
w3m-el-snapshot:

    Package: *
    Pin: release a=testing
    Pin-Priority: -10

    Package: w3m-el-snapshot
    Pin: release a=testing
    Pin-Priority: 800

But is there a way to find out/confirm from
which release is a certain pack? I know about
'aptitude show' but save for the version, which
I suppose one could Google and compare (poor
man's solution IMO), it doesn't seem to say
what I can see.

Neither does 'dpkg -l'.

So is there a way to do this with shell
tool(s)?

TIA


[1] https://wiki.debian.org/AptPreferences

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