diff --git a/openpgp-card/src/card_app.rs b/openpgp-card/src/card_app.rs
index 0fdb02b..4093773 100644
--- a/openpgp-card/src/card_app.rs
+++ b/openpgp-card/src/card_app.rs
@@ -18,7 +18,7 @@ use crate::errors::OpenpgpCardError;
 use crate::tlv::{tag::Tag, Tlv, TlvEntry};
 use crate::{apdu, keys, CardCaps, CardClientBox, KeyType};
 
-/// Direct, low-level, access to OpenPGP card functionality.
+/// Low-level access to OpenPGP card functionality.
 ///
 /// No checks are performed here (e.g. for valid data lengths).
 /// Such checks should be performed on a higher layer, if needed.
diff --git a/openpgp-card/src/card_data/mod.rs b/openpgp-card/src/card_data/mod.rs
index e133aa0..5426d92 100644
--- a/openpgp-card/src/card_data/mod.rs
+++ b/openpgp-card/src/card_data/mod.rs
@@ -352,6 +352,7 @@ impl<T> KeySet<T> {
     }
 }
 
+/// nom parsing helper
 pub(crate) fn complete<O>(result: nom::IResult<&[u8], O>) -> Result<O, Error> {
     let (rem, output) =
         result.map_err(|err| anyhow!("Parsing failed: {:?}", err))?;
diff --git a/openpgp-card/src/errors.rs b/openpgp-card/src/errors.rs
index 5ed6141..652fcdd 100644
--- a/openpgp-card/src/errors.rs
+++ b/openpgp-card/src/errors.rs
@@ -1,13 +1,13 @@
 // SPDX-FileCopyrightText: 2021 Heiko Schaefer <heiko@schaefer.name>
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
-//! Error types that are used by this crate.
+//! Error types used by this crate.
 //!
 //! [`OpenpgpCardError`] is a wrapper enum for all error types that are used.
 //!
-//! The two main cases are:
+//! The two main classes of errors are:
 //! - [`SmartcardError`], for problems on the reader/smartcard layer
-//! - [`OcErrorStatus`] which models error statuses reported by the OpenPGP
+//! - [`OcErrorStatus`], which models error statuses reported by the OpenPGP
 //! card application
 
 use thiserror::Error;
diff --git a/openpgp-card/src/lib.rs b/openpgp-card/src/lib.rs
index 7a2a804..572dcd2 100644
--- a/openpgp-card/src/lib.rs
+++ b/openpgp-card/src/lib.rs
@@ -41,7 +41,7 @@ pub use crate::card_app::CardApp;
 
 /// The CardClient trait defines communication with an OpenPGP card via a
 /// backend implementation (e.g. the pcsc backend in the crate
-/// openpgp-card-pcsc).
+/// [openpgp-card-pcsc](https://crates.io/crates/openpgp-card-pcsc)).
 pub trait CardClient {
     /// Transmit the command data in `cmd` to the card.
     ///
@@ -71,9 +71,13 @@ pub trait CardClient {
     }
 }
 
+/// A boxed CardClient (which is Send+Sync).
 pub type CardClientBox = Box<dyn CardClient + Send + Sync>;
 
-/// Information about the capabilities of the card.
+/// Configuration of the capabilities of the card.
+///
+/// This configuration is used to determine e.g. if chaining or extended
+/// length can be used when communicating with the card.
 ///
 /// (This configuration is retrieved from card metadata, specifically from
 /// "Card Capabilities" and "Extended length information")