Dear Houdini

node = hou.pwd()
geo = node.geometry()

geo.createPacked("PackedDisk")

int ptnum = addpoint(geoself(), {0,0,0});
int primnum = addprim(geoself(), "PackedDisk", ptnum);

//Display as bounding box
setprimintrinsic(geoself(), "viewportlod", @primnum, "box", "set");

int f = @Frame-1;
string ver = sprintf("%04d", f);
setprimintrinsic(geoself(), "unexpandedfilename", @primnum, "/hou/foo/obj_" + ver +".bgeo.sc", "set");

string file = primintrinsic(geoself(), "unexpandedfilename", @primnum);

string ver = sprintf("%04d", @Frame);

int idx = find(file, ver);

if(idx!=-1)
{
    ver = sprintf("%04d", @Frame + ch("offset"));
    
    file = file[:idx] + ver + file[idx+4:];
    setprimintrinsic(geoself(), "unexpandedfilename", @primnum, file, "set");
    
}

s@path = "/aa/bb/ccc/alembic.abc";

In python, we can get object paths of cxform, xform, camera, polymesh, subdmesh, faceset, curves, points and nupatch.
(unknown is no readable).
For now, the best way is to add these paths to a string attribute with "," for seperation.

node = hou.pwd()
geo = node.geometry()

geo.addAttrib(hou.attribType.Point, "objpath","")

import _alembic_hom_extensions as abc

for pt in geo.points():
    abcPath = pt.stringAttribValue("path")
    paths = abc.alembicGetObjectPathListForMenu(abcPath)

    meshPath = ""
    
    for i in range(0,len(paths),2):
        path = paths[i]
        hie = abc.alembicGetSceneHierarchy(abcPath, path)
        if hie[1] == "polymesh":
            if meshPath != "":
                meshPath += ","
    
            meshPath += path
            
    pt.setAttribValue("objpath", meshPath)

At least, there are 3 intrinsic attributes to modify to read an alembic file properly.

int primnum = addprim(geoself(), "AlembicRef", ptnum);

//setprimintrinsic(geoself(), "viewportlod", primnum, "box", "set");
setprimintrinsic(geoself(), "abcfilename", primnum, s@path, "set");
setprimintrinsic(geoself(), "abcframe", primnum, @Frame*@TimeInc, "set");
setprimintrinsic(geoself(), "abcobjectpath", primnum, objpath[n], "set");

Rotate Packed Primitives with orient.

string atrs[] = detailintrinsic(geoself(), "pointattributes");
int find[] = find(atrs, "orient");
if(len(find) >0)
{
    matrix3 mat = qconvert(vector4(point(0,"orient", @ptnum)));
    setprimintrinsic(geoself(), "transform", primnum, mat, "set");
}

01_read_packed_disk_v01_02