You can check fragmented packets as suggested in the video by tapping RX path in net/core/dev.c – __netif_receive_skb_core() API as shown below from the Kernel-source version 6.5.9:
static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc,
struct packet_type **ppt_prev)
{
...
//thelinuxchannel - start
if(skb_shinfo(skb)->nr_frags) { printk("skb - is fragmented !\n"); }
//thelinuxchannel - end
...
}