Mycelium
Mycelium is best known for its mobile Bitcoin wallet. The wallet remains published at wallet.mycelium.com, which offers a direct Android APK and a Google Play listing for the package com.mycelium.wallet.[1] Source is on GitHub. The repository path mycelium-com/wallet redirects to mycelium-com/wallet-android.[2][3] The download page says the group started in 2008 as a hardware-engineering team working on a mesh network, then moved into Bitcoin. It says the wallet, Entropy, and Gear are three products it has launched in bitcoin.[1]
Wallet
The README describes a non-custodial Deterministic wallet using BIP32 and BIP44 accounts and a BIP39 master seed. It says private keys stay on the phone unless the user exports them, and that the app does not download the full block chain. It reaches Bitcoin through servers the project calls super nodes, including over a Tor hidden service. Users can import watch-only addresses and extended public keys, spend from a Paper wallet, spend from a Trezor account, and spend Shamir secret-shared 2-of-3 keys produced for Mycelium Entropy. Balances can be shown in BTC, mBTC, bits, and uBTC, and in a list of fiat currencies. The user sets the miner fee. Message signing is described as compatible with bitcoin-qt. The same file lists an address book, a QR-code scanner, and the option to type an amount in fiat and switch to bitcoin while entering it.[3]
The download page adds Segregated Witness addresses in native Bech32 and in P2SH form, hardware-wallet support for Trezor, Ledger, and KeepKey, several levels of PIN protection, and a fee-bump option that uses child-pays-for-parent. It lists Ethereum and selected ERC-20 tokens, FIO names, NFC, and an in-app exchange. It says no identity document is required and that third-party services can be turned off. It also says the app can show unspent outputs, export a transaction history to CSV, and offer more than one block-explorer option.[1]
Release builds are signed with one certificate. The README prints the signer certificate SHA-256 digest b8e59d4a60b65290efb2716319e50b94e298d7a72c76c2119eb7d8d3afac302e and a distinguished name of CN=Mycelium Developers, O=Mycelium, L=Vienna, C=AT. It documents a Podman and disorderfs procedure for rebuilding the Play Store package and comparing it with a local build.[3] The download page prints the same digest and offers the APK both as a direct file and through Obtainium.[1]
Other sites
The company homepage still links Gear, Entropy, a card network, and a product called Swish beside the wallet.[4] Gear, at gear.mycelium.com, presents itself as a bitcoin payment processor whose widget and API send a customer's payment straight into a wallet the merchant controls. The page says Gear does not hold the merchant's keys and does not require the merchant to complete KYC or AML procedures before accepting bitcoin. Its footer still carries a 2015-2017 copyright line.[5] The Entropy page describes a small USB device that uses hardware entropy to print bitcoin paper wallets.[6] The homepage describes Swish as an online and in-store ordering and payment system for fiat and digital assets.[4] The card site describes a smart card and hub for payments and says that system does not use cryptocurrencies. It says the units on that network are digital tokens backed by an issuing institution.[7]