It means that when the Russian-Ukrainian war was at a stalemate, Lithuania, one of the three Baltic countries, announced that it would strictly abide by the ban on sanctioning Russian goods and prohibit the goods on the sanctions list from entering Lithuania. This seems to be the same policy as that of neighboring countries, but it immediately caused a violent backlash from Russia. Because Kaliningrad, an important strategic location in Russia, is an enclave and is not connected to the Russian mainland. Most of the necessities of life must be transported from the Russian mainland to Kaliningrad via Belarus and Lithuania.
Once Lithuania imposes such a ban, It is equivalent to blocking the communication route between Russia and Kaliningrad. As soon as the raster to vector conversion news came out, the residents of Kaliningrad panicked and began to rush into supermarkets to buy various civilian supplies. Russia also threatened to retaliate violently. The strategic importance of Kaliningrad has already been explained in the previous " Illustrating Russia's Long-Term Strategic Map " and will not be repeated here. Historically, this enclave originally belonged to Germany.
After the end of World War II, the defeated Nazi Germany ceded part of its territory to Poland and the Soviet Union. The part obtained by the Soviet Union was renamed Kaliningrad. At the time, Kaliningrad was not an enclave, as the Soviet Red Army "recaptured" Lithuania from Nazi Germany. The main reason is that Lithuania was already annexed by Russia during the Tsarist period, and only during the First World War, Lithuania was occupied by Germany. So when the Iron Curtain fell, Lithuania, like Latvia and Estonia, was forced to become a republic of the Soviet Union. Therefore, in the former Soviet Union, Kaliningrad was not an enclave, and traveling to Kaliningrad from Lithuania was equivalent to traveling within the Soviet Union.