Minecraft Command NBT Array Add
Solution 1:
1.14 introduces this feature using the "append" mode of /data modify:
/data modify entity @e[type=item,limit=1] Item.tag.display.Lore append value "{\"text\":\"second line\"}"
1.14 introduces this feature using the "append" mode of /data modify:
/data modify entity @e[type=item,limit=1] Item.tag.display.Lore append value "{\"text\":\"second line\"}"