/usr/share/accounts/services/picasa.service is in account-plugin-google 0.11+14.04.20140409.1-0ubuntu1.
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 17 18 19 20 21 22 23 24 25 26 27 | <?xml version="1.0" encoding="UTF-8"?>
<service id="service">
  <type>sharing</type>
  <name>Picasa</name>
  <icon>icon_picasa</icon>
  <provider>google</provider>
  <translations>account-plugins</translations>
  
  <template>
    <group name="auth">
      <group name="oauth2">
        <group name="user_agent">
          <setting type="as" name="Scope">["https://picasaweb.google.com/data/"]</setting>
        </group>
      </group>
      <group name="google">
        <group name="ClientLogin">
          <setting name="Service">lh2</setting>
          <setting name="Source">Ubuntu-sharing-1.0</setting>
        </group>
      </group>
    </group>
  </template>
</service>
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