Unpack/pack .pak .espak?

I have these files and I must unpack/pack these files… or can I use it in Urho3D

pak has a format like ULZ4
espak has a format like ELZ4

my info.json shows:

“DistributionInfo”: {
“DistributionName”: “Studio_1”,
“PackageFile”: “Studio_1.espak”,
“Custom”: false,
“DistributeDate”: “Thu Nov 30 09:20:20 2017”,
“CoverInfosCount”: 0,
“CoverInfos”: [],
“StudioInfosCount”: 2,
“StudioInfos”: [
“Name”: “Studio_1.xml”,
“ScenePath”: “Scenes/Studio_1.xml”,
“ImagePath”: “Studio_1.jpg”
“Name”: “Studio_1_Widescreen.xml”,
“ScenePath”: “Scenes/Studio_1_Widescreen.xml”,
“ImagePath”: “Studio_1_Widescreen.jpg”

someone can tell me from the dev, how I unpack/pack these files?

thx very much

ok I have analysis the file, how can I unpack .pak???