What is it?

Every Hunter release (Atom feed) archive is a meta-package with build instructions and URLs of real packages. The archive will be downloaded and unpacked automatically by the HunterGate CMake module. You only need to set the URL and SHA1:

HunterGate(
    URL "https://github.com/cpp-pm/hunter/archive/v0.23.297.tar.gz"
    SHA1 "3319fe6a3b08090df7df98dee75134d68e2ef5a3"
)

Here is the content of the archive in simplified form:

Hunter (0.23.297) = {
    Boost (1.65.1, 1.65.0, 1.66.0, 1.66.0-p0, 1.67, ...),
    GTest (1.7.0, ...),
    OpenCV (4.1.1-p0, 4.0.0-p3, 3.4.6-p0, ...),
    OpenSSL (1.1.1, 1.1.1a, 1.1.1b, 1.1.1c, 1.1.1d, 1.1.1g, 1.1.1g-p0, ...),
    ...
}

If you download and unpack it, you can view some internals. Let’s look at the OpenSSL package properties:

wget https://github.com/cpp-pm/hunter/archive/v0.14.5.tar.gz
tar xf v0.14.5.tar.gz

hunter.cmake holds the list of available versions:

grep -A3 -m3 VERSION hunter-0.14.5/cmake/projects/OpenSSL/hunter.cmake
    VERSION
    "1.1.1"
    URL
    "https://github.com/openssl/openssl/archive/OpenSSL_1_1_1.tar.gz"
--
    VERSION
    "1.1.1a"
    URL
    "https://github.com/openssl/openssl/archive/OpenSSL_1_1_1a.tar.gz"
--
    VERSION
    "1.1.1b"
    URL
    "https://github.com/openssl/openssl/archive/OpenSSL_1_1_1b.tar.gz"

Install instructions from build scheme url_sha1_openssl.cmake.in:

grep -A1 INSTALL_COMMAND hunter-0.14.5/cmake/projects/OpenSSL/schemes/url_sha1_openssl.cmake.in
INSTALL_COMMAND
make install_sw

Default version from default.cmake (is customizable, see Config-ID):

grep '\<OpenSSL\>' -m1 hunter-0.14.5/cmake/configs/default.cmake
hunter_default_version(OpenSSL VERSION 1.1.1)