eidklient working PKGBUILD (simplified, one arch only)

pkgname=eidklient
pkgver=4.4
pkgrel=1
pkgdesc="Slovak eID Client"
arch=('x86_64')
url="https://www.slovensko.sk/"
license=('custom')
source=('https://eidas.minv.sk/downloadservice/eidklient/linux/eID_klient-x86_64.AppImage')
sha256sums=('912815b782eba6ea149e73c3ace67a4febce3e092edde0f0c9c061f9ba1dd03a')
options=("!strip")

FILENAME="eID_klient-x86_64.AppImage"

prepare() {
    chmod +x "${srcdir}/${FILENAME}"
    pushd "${srcdir}"
    "./${FILENAME}" --appimage-extract
    popd
}

package() {
    install -Dm755 "${srcdir}/${FILENAME}" "${pkgdir}/opt/appimages/${FILENAME}"

    install -Dm755 "${srcdir}/squashfs-root/lib/libCardAPI.so" "${pkgdir}/usr/lib/eidklient/libCardAPI.so"
    install -Dm755 "${srcdir}/squashfs-root/lib/libbotan.so" "${pkgdir}/usr/lib/eidklient/libbotan.so"
    install -Dm755 "${srcdir}/squashfs-root/lib/libpkcs11_x64.so" "${pkgdir}/usr/lib/eidklient/libpkcs11_x64.so"
    install -Dm644 "${srcdir}/squashfs-root/lib/libcrypto.so.1.0.2" "${pkgdir}/usr/lib/eidklient/libcrypto.so.1.0.2"
    install -Dm644 "${srcdir}/squashfs-root/lib/libssl.so.1.0.2" "${pkgdir}/usr/lib/eidklient/libssl.so.1.0.2"

    # VirtualKeyboard program seems to not work, eID application is used in its place instead
    ln -s "/opt/appimages/${FILENAME}" "${pkgdir}/usr/lib/eidklient/VirtualKeyboard"
    mkdir "${pkgdir}/usr/bin"
    ln -s "/opt/appimages/${FILENAME}" "${pkgdir}/usr/bin/VirtualKeyboard"

    install -Dm644 "${srcdir}/squashfs-root/sk_logo.svg" "${pkgdir}/usr/lib/eidklient/img/icon.svg"
    # Custom file included in the PKGBUILD's directory, can be replaced by the one included in the AppImage
    install -Dm644 "${srcdir}/../eidklient.desktop" "${pkgdir}/usr/share/applications/eidklient.desktop"
}