Streamlit

Official docs outline

Basic Concepts
Running a Streamlit app, data flow, displaying data, widgets, layout, and the rerun model.
Architecture and Execution Flow
Script reruns on interaction, top-to-bottom execution, and how the app executes.
Architecture
Server, browser frontend, sessions, websocket connection, and threading model.
Widget Behavior
Widget keys, identity, state, callbacks, forms, and widget reset behavior.
Session State
st.session_state, initializing state, callbacks, and persisting values across reruns.
Caching
st.cache_data and st.cache_resource, hashing arguments, ttl, and avoiding repeated computation.
Fragments
st.fragment, partial reruns, run_every, and isolating interactions from full app reruns.
Multipage Apps
pages directory, st.Page and st.navigation, page routing, and sharing state between pages.
App Design
Layout, columns, tabs, containers, dialogs, and design patterns for apps.
Connections and Secrets
st.connection, secrets.toml, SQL and API data sources, and credential handling.
Configuration and Theming
config.toml, server and browser options, themes, and fonts.
Custom Components
Building components with JavaScript and React, bidirectional components, and component packaging.
App Testing
AppTest framework, simulating widget interactions, and testing in CI.
Async and Multithreading
Using threads in apps, script run contexts, and background work.
Deploy Your App
Community Cloud, Docker, other hosts, and deployment configuration.

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.