diff --git a/metadata/README.md b/metadata/README.md
--- a/metadata/README.md
+++ b/metadata/README.md
@@ -1,228 +1,233 @@
 Metadata format
 ===============
 
 We're using the [TOML](https://toml.io/en/v1.0.0) format for metadata files. The data model is
 defined in Isabelle/Scala, so larger changes can also be done in a programmatic way.
+You can also use the web-based user interface to edit the metadata,
+which can be started locally with `isabelle afp_edit_metadata`
+(though some fields can not be edited this way, such as the history) --
+on a save, the tool will overwrite the metadata in your repository clone.
+
 
 `entries/<name>.toml`
 ---------------------
 
 Storage for entry metadata. Format:
 
 ```toml 
 title = "<text>"
 date = <YYYY>-<MM>-<DD>
 topics = ["<topic>/<subtopic>/...", "<topic2>/..."]
 abstract = """
 <multiline text>
 """
 license = "<license>"
 note = "<text>"
 [authors]
 [contributors]
 [notify]
 [history]
 [extra]
 [related]
 ```
 
 Optional:
 
 - ```toml
   statistics_ignore = <bool>
   ```
 - in `[authors]` and `[contributors]`:
   ```toml
   [authors.<author_id>]
   homepage = "<homepage_id>"
   email = "<email_id>"
   ```
 - in `[notify]`:
   ```toml
   <author_id> = "<email_id>"
   ```
 - in `[history]`:
   ```toml
   <YYYY>-<MM>-<DD> = "<text>"
   ```
 - in `[extra]`:
   ```toml
   extra-<key> = "<heading>: <text>"
   ```
 - in `[related]`:
   ```toml
   dois = [ "<doi>", ... ]
   pubs = [ "<text>", ... ] 
   ```
 
 [Example](/metadata/entries/Presburger-Automata.toml)
 
 Details:
 
 - **name**:
   The toml file name (`<short-name>` in this terminology) must correspond to the folder name
   in `thys` directory. This short name is used as entry identifier during the whole process.
 
 - **date**:
   The date is the submission date of the entry.
 
 - **topics**:
   Currently, only three levels of topics and subtopics are allowed, but you may specify as many
   topics as you wish. If multiple topics are specified, the entry will appear under each of them.
   The topic must also appear in the `topics` file (see below).
 
 - **license**:
   Allowed values for the license are "bsd" and "lgpl".
 
 - **authors**:
   Authors and affiliations must appear in the `authors` file (see below). For each author, you may
   provide an affiliation as homepage and/or email.
 
 - **contributors**:
   Sometimes existing entries get significant contributions from other authors. These authors can be
   listed on a 'contributors' line. A separate change-history entry should indicate what these people
   have contributed.
 
 - **extra**:
   If you want to have some additional text fields below the 'Abstract' column, you can use
   the `extra` facility, where `<key>` denotes an identifier (most cases 0, 1, ...) unique for each
   entry. The particular
   `<key>` has no impact on output and is solely used for disambiguating multiple extra fields.
 
   Example:
   ```toml
   extra-0 = "Warning: Untested..."
   ```
 - **related**:
   A Place for references related to this article, e.g., print publications. DOIs are preferred and
   stored by name only (e.g., `10.1000/182`). If there is none, use a formatted citation (html tags
   are allowed).
 
 `topics.toml`
 -------------
 Each topic and its subtopics must go into there. Format:
 
 ```toml
 ["First level topic"]
 
 ["First level topic".classification]
 <classification>
 
 ["First level topic"."Second level topic"]
 
 ["First level topic"."Second level topic".classification]
 <classification>
 
 ["First level topic"."Second level topic"."Third level topic"]
 
 ["First level topic"."Second level topic"."Third level topic".classification]
 <classification>
 
 ["First level topic"."Another second level topic"]
 
 ["First level topic"."Another second level topic".classification]
 <classification>
 ```
 
 Topics without space may omit quotes. Only three levels of indentation are supported currently.
 
 Optional:
 - in `[<...>.classification]`:
   - AMS:
     ```toml
     ams.id = "<id>"
     ams.hierarchy = [
       "<descriptions>",
     ]
     ```
   - ACM:
     ```toml
     acm.id = "<id>"
     acm.desc = "<description>"
     ```
 
 Details:
 - **classification**:
   A corresponding topic for each AMS and ACM subject classification can be put here.
   - AMS:
     Data comes from [MSC2020 database](https://mathscinet.ams.org/mathscinet/msc/msc2020.html). IDs
     are used without `-XX` or `xx`. In the hierarchy, descriptions are stored for each level (text 
     in `{...}` is omitted), top level first.
   - ACM:
     Data comes from [2012 ACM CCS](https://dl.acm.org/ccs), and the fields can be directly copied 
     from the xml output.
 
 
 `authors.toml`
 --------------
 Name, alphanumeric short name, and affiliations for each author. Format:
 
 ```toml
 [<shortname>]
 name = "<name>"
 [<shortname>.emails]
 [<shortname>.homepages]
 ```
 
 Optional:
 - in `[<shortname>]`:
   ```toml
   orcid = "<id>"
   ```
 - in `[<shortname>.emails]`:
   ```toml
   [<shortname>.emails.<id>]
   user = [
     <parts>
   ]
   host = [
     <parts>
   ]
   ```
 - in `[<shortname>.homepages]`:
   ```toml
   <id> = "<url>"
   ```
 
 Example:
 ```toml
 [huch]
 name = "Fabian Huch"
 orcid = "0000-0002-9418-1580"
 
 [huch.emails]
 
 [huch.emails.huch_email]
 user = [
   "huch",
 ]
 host = [
   "in",
   "tum",
   "de",
 ]
 
 [huch.homepages]
 huch_homepage = "https://home.in.tum.de/~huch"
 ```
 
 Details:
 - **shortname**:
   Author shortnames are derived from last name and characters from the first name until unique,
   e.g. `haslbeck` and `haslbeckm`. Homepage and email ids are usually of form `<shortname>_email` (
   or `<shortname>_homepage`) and are incremented for multiples, e.g. `haslbeckm_email1`.
 - **orcid**:
   Orcid id, identifier only.
 - **parts**:
   User and host are represented as lists of parts split by dots. 
 
 
 `releases.toml`
 ---------------
 Contains all releases. The youngest release is always ignored, so don't forget to add old releases
 when a new Isabelle version is released. Format:
 
 ```toml
 [name]
 <yyyy>-<mm>-<dd> = <isabelle-release>
 ```