How can I see what is bitcoin tx for pending Lighting channel (lnd)
The output of lncli pendingchannels gives you as much as you need:

"pending_open_channels": [
{
        "channel": {
            "remote_node_pub": &lt;pubkey&gt;,
            "channel_point": &lt;txid:output_index&gt;,
            "capacity": ,
            "local_balance": ,
            "remote_balance": 
        },
        "confirmation_height": ,
        "commit_fee": ,
        "commit_weight": ,
        "fee_per_kw": 
}]


The channel_point will give you the txid, that you can later lookup at a bitcoin testnet explorer, or directly with btcctl --testnet gettransaction txid