Update MetAcsl's description

_fc-plugins/metacsl.md

 ---
 layout: plugin
 title: MetAcsl
-description: Verification of meta-properties
+description: Verification of high-level ACSL requirements
 key: specifications
-distrib_mode: proto
+distrib_mode: free
 repo_url: https://git.frama-c.com/pub/meta
 ---
 
 ## Overview
 
 MetAcsl is a plug-in dedicated to specifying and verifying
-*meta-properties*, that is, properties that are supposed
+*high-level ACSL requirements* (HILARE), that is, properties that are supposed
 to be checked at many points of the code base under analysis,
 so that writing the corresponding ACSL annotations manually
 would be extremely tedious and error-prone. A simple example
-of such a property would be a confidentiality property indicating
+of such a requirement would be a confidentiality property indicating
 that no access to a particular memory block should occur unless
 some clearance condition holds. Specifying that in pure ACSL
 would require writing an assertion for each read access in the
-code, while MetAcsl only needs a single meta-property.
+code, while MetAcsl only needs a single HILARE.
 
 In summary, MetAcsl defines a global ACSL extension for describing
-meta properties, that are composed of three things:
+HILAREs, that are composed of three elements:
 
-- a target: the set of functions where the meta-property should hold;
+- a target: the set of functions where the HILARE should hold;
 
 - a context: the kind of program points that are concerned by the
-meta-property. Two important contexts are `\writing` and
+HILARE. Two important contexts are `\writing` and
 `\reading` accesses;
 
 - the property itself: it is an ACSL predicate, possibly enriched
@@ -35,13 +35,13 @@ a `\writing` context gives rise to a `\written`
 meta-variable denoting the location being written to.
 
 The plug-in proceeds by generating all ACSL annotations corresponding to
-each meta-property. It is then possible to use one of the main analysis
+each HILARE. It is then possible to use one of the main analysis
 plug-ins of the platform (e.g. [WP](wp.html),
 [E-ACSL](e-acsl.html), or [Eva](eva.html)) to
 verify these annotations.
 
 ## Usage
 
-MetAcsl is available as a separate open-source plug-in, on [Gitlab](https://git.frama-c.com/pub/meta).
+MetAcsl is available as a separate open-source plug-in, on [Gitlab](https://git.frama-c.com/pub/meta) (more information here).
 It is intended to be compatible with the latest state of [Frama-C's public repository](https://git.frama-c.com/pub/frama-c).
-Once installed, the plugin is activated by the `-meta` option, which will parse the meta-properties and generate the corresponding ACSL annotations.
\ No newline at end of file
+Once installed, the plugin is activated by the `-meta` option, which will parse the meta-properties and generate the corresponding ACSL annotations.