If you are working on macOS the .trash folder in Obsidian is in the folder, where you save your notes = Vault. To access the .trash you have to activate the invisible files.
CMD + Shift + .
Now you see the folders “.trash” and “.obsidian” (and every other hidden folder and files). Also in the hidden obsidian folder are the plugins located. To redo this, just press the Shortcut again.