Neovim is a modal text editor whose editing state consists of buffers, windows and tab pages. A buffer holds text, a window displays a buffer, and a tab page arranges windows. Closing a window therefore does not necessarily delete the buffer or its unsaved state. Lua, Vimscript and remote APIs can change the same editor instance, while terminal buffers and language tools add other processes around it.
Windows do not equal files
One buffer can appear in several windows, and one tab page can contain several window splits. Commands that close a view, unload a buffer or delete a buffer have different consequences. This model supports side-by-side views of the same text, but it also makes a familiar close action less obvious to a new user.
A terminal session runs inside a special buffer backed by libvterm. Its output arrives asynchronously, and terminal input goes to the running application rather than editing the buffer like ordinary text. Terminal applications also cannot read the system clipboard through OSC 52 in the documented terminal path.
Language intelligence needs external servers
The built-in LSP client connects a buffer to separately installed language-server executables. It can expose navigation, diagnostics, completion and code actions after configuration establishes the command and root. Neovim does not bundle a server for every language, so enabling the client without installing the executable leaves the buffer without those responses.
Tree-sitter incrementally parses a buffer and can drive highlighting or language-aware selections. Only a small core set of parsers ships with Neovim. Other languages need separate parser installation, often through a plugin. The documentation labels the integration experimental, so parser APIs and behavior can change more often than ordinary editing commands.
Runtime files become active code
Lua or Vimscript placed in a runtime plugin directory loads without a separate plugin manifest. This makes a small local extension easy to start, but every discovered script can execute during startup. Renaming a test file into that directory changes it from stored code into active editor configuration.
Neovim exposes its API through Lua, Vimscript and MessagePack-RPC. A graphical client or remote plugin can control buffers and windows in an existing instance. API callers still need to distinguish buffer handles, window handles and tab-page handles when they change state. The remote command treats arguments after --remote as file names and does not implement the documented wait variants, so shell automation cannot assume every remote-client convention exists.
The same extensibility creates separate failure layers. Syntax highlighting can work through Tree-sitter while LSP completion fails because the server is absent. A terminal can run successfully while its special buffer refuses an ordinary edit. Inspecting which layer owns the behavior avoids replacing the entire configuration for one missing component.
