There is a semantic way of using tab characters in source code: tabs for indentation, spaces for alignment. This package provides a minor mode which improves Emacs' auto-indenting so that pressing TAB inserts the correct mix of tabs and spaces to maintain visual alignment regardless of a viewer's tab width. You can still use all spaces if you prefer; the code merely ensures that if you enable tabs, the tab size does not matter.

This package provides provides variants of eval-last-sexp that work on the containing list or s-expression, as well as an option for visually flashing evaluated s-expressions.

The minitest mode provides commands to run the tests for the current file or line, as well as rerunning the previous tests, or all the tests for a project.

This package also includes relevant snippets for yasnippet.

This package provides tools to save and restore frame and window configurations in Emacs, including buffers that may not be live anymore. In this way, it's like a lightweight "workspace" manager, allowing you to easily restore one or more frames, including their windows, the windows' layout, and their buffers.

gitlab-ci-mode is an Emacs major mode for editing GitLab CI files. It provides syntax highlighting and completion for keywords and special variables. An interface to GitLab’s CI file linter is also provided via gitlab-ci-lint.

Daredevil SKK is a version of SKK, a Japanese input method on Emacs. This package adds support for the Nicola keyboard layout to it.

This package provides support for the Puppet configuration language, including syntax highlighting, indentation of expressions and statements, linting of manifests and integration with Puppet Debugger.

This package provides on-the-fly syntax checking for GNU Emacs. It is a replacement for the older Flymake extension which is part of GNU Emacs, with many improvements and additional features.

Flycheck provides fully-automatic, fail-safe, on-the-fly background syntax checking for over 30 programming and markup languages with more than 70 different tools. It highlights errors and warnings inline in the buffer, and provides an optional IDE-like error list.

EMMS is the Emacs Multimedia System. It is a small front-end which can control one of the supported external players. Thus, it supports whatever formats are supported by your music player. It also supports tagging and playlist management, all behind a clean and light user interface.

This package provides an Emacs Ivy extension, which let Ivy use posframe to show its candidate menu.

This package provides two commands using Consult to query Notmuch emails and present results either as single emails or full trees.

GNU Hyperbole, or just Hyperbole, is a programmable hypertextual information management system. It offers rapid views and interlinking of all kinds of textual information, utilizing Emacs for editing. In particular, Hyperbole lets you quickly create and activate hyperlink buttons, build outlines, manage all your contacts, your windows and frames, and search across buffers, directory trees, or the web.

This package provides the hydra-ivy/body command, which is a quasi-prefix map, with many useful bindings. These bindings are shorter than usual, using mostly unprefixed keys.

This package provides a Helm interface for selecting xref results.

This package renders an indicator with an email count of the notmuch index on the Emacs mode line. The underlying mechanism is that of notmuch-count, which is used to find the number of items that match the given search terms.

This package enables you to associate file name patterns with external applications that are automatically invoked when you use commands like find-file. For example, you can have it open png files with feh and mp4 files with mpv. This is especially useful when browsing files with Dired.

The Emacs IPython Notebook (EIN) package provides a Jupyter Notebook client and integrated REPL (like SLIME) in Emacs. EIN improves notebook editing by allowing you to use Emacs. It also expose IPython features such as code evaluation, object inspection and code completion. These features can be accessed anywhere in Emacs and improve Python code editing and reading in general in Emacs.

This package provides a testeable Emacs Lisp API that wraps GNU Global calls and integration to editor using this API with project.el and xref.el.

org-margin mode outdents org headlines by moving leading stars into the margin and transform them into markers depending on the chosen style.

emacs-pyimport manages python imports from Emacs via python-pyflakes.

emacs-org-brain implements a variant of concept mapping in Emacs, using org-mode. An org-brain is a network of org-mode entries, where each entry is a file or a headline, and you can get a visual overview of the relationships between the entries: parents, children, siblings and friends. This visual overview can also be used to browse your entries. You can think of entries as nodes in a mind map, or pages in a wiki.

This package contains add-ons to Org. Be warned that these libraries receive little if no maintenance and there is no guaranty that they are compatible with the Org stable version.

Org Tree Slide is a minor mode for using an Org document in presentations by progressively revealing individual subtrees of the document.

This package displays a calendar view with various schedule data in the Emacs buffer.