The mod Transport Drones (Continued) (2.0.50) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Transport_Drones_Continued::on_tick (ID 0)
Transport_Drones_Continued/script/depot_base.lua:1048: attempt to index field '?' (a nil value)
stack traceback:
Transport_Drones_Continued/script/depot_base.lua:1048: in function 'get_requested_item'
...sport_Drones_Continued__/script/depots/request_depot.lua:139: in function 'check_request_change'
...sport_Drones_Continued__/script/depots/request_depot.lua:125: in function 'update'
Transport_Drones_Continued/script/depot_common.lua:489: in function 'update_depots'
Transport_Drones_Continued/script/depot_common.lua:574: in function 'handler'
core/lualib/event_handler.lua:72: in function <core/lualib/event_handler.lua:70>

Save file to reproduce:
https://drive.google.com/file/d/1g_0LUa0g3epAZOYaISzO85aC_c4C8q6_/view?usp=sharing

I temporary applied this fix (from ChatGPT), that fixed the problem temporary....:

 script/depot_base.lua | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/script/depot_base.lua b/script/depot_base.lua
index 1287252..38920f1 100644
--- a/script/depot_base.lua
+++ b/script/depot_base.lua
@@ -1030,7 +1030,10 @@ function requester:set_request_mode()
   local recipe = self.entity.get_recipe()
   if not recipe then return end

-  local product_type = recipe.products[1].type
+  local product = recipe.products and recipe.products[1]
+  if not product then return end
+
+  local product_type = product.type
   if product_type == "item" then
     self.mode = depot_base.request_mode.item
     return
@@ -1045,7 +1048,9 @@ end
 function requester:get_requested_item()
   local recipe = self.entity.get_recipe()
   if not recipe then return end
-  return recipe.products[1].name
+  local product = recipe.products and recipe.products[1]
+  if not product then return end
+  return product.name
 end

 function requester:update_circuit_writer()

Hopefully fixed in 2.0.52