APKs in this directory are used by PkgInstallSignatureVerificationTest.
See that class for additional information about their use.

In general, they are differently signed forms of the tinyapp APK and follow
the following naming scheme:

${version}-with-${signing-algorithm}-${OID-params}-${keysize}-${extra_info}

where some fields may not be present, but have the following meaning:

version: denotes which APK Signature Scheme (v1, v2, and/or v3) was used
signing-algorithm: indicates how the signature was generated
OID-params: PKI object identifiers indicating how to use the provided key
  to generate the signature.  See, e.g. rfc3279 and rfc4055.
keysize: the size of the key used for signing
extra_info: additional notes to distinguish packages. Currently this denotes
  which test certificates were used to generate a proof-of-rotation object,
  if one exists, included in the signing block of the APK, as well as the
  capabilities of those certificates according to APK Signature Scheme v3.

Generation of these apks was performed using the apksigner command-line tool,
which lives at tools/apksig/src/apksigner/java/com/android/apksigner/ in the
android source tree.  Please refer to the usage instructions there for how to
sign APKs using different keystores, providers, etc.  In particular, some of
the APKs in this directory were generated by modifying the apksig library (see
README in tools/apksig/) to create invalid or unsupported outcomes.