diff --git a/Library/Homebrew/cache_store.rb b/Library/Homebrew/cache_store.rb
index 57b319248f..1a9cf3be68 100644
--- a/Library/Homebrew/cache_store.rb
+++ b/Library/Homebrew/cache_store.rb
@@ -7,7 +7,9 @@ require "json"
 #
 class DatabaseCache
   # The mode of any created files will be 0664 (that is, readable and writable
-  # by the owner and the group, and readable by everyone else)
+  # by the owner and the group, and readable by everyone else). Files created
+  # will also be modified by the process' umask value at the time of creation:
+  #   https://docs.oracle.com/cd/E17276_01/html/api_reference/C/envopen.html
   DATABASE_MODE = 0664
 
   # Opens and yields a database in read/write mode. Closes the database after use
@@ -66,13 +68,13 @@ class CacheStore
   # into a JSON compatible string in `ruby_hash_to_json_string`, where it may
   # later be parsed by `JSON.parse` in the `json_string_to_ruby_hash` method
   #
-  # @param  [Hash]
+  # @param  [Hash] ruby `Hash` to be converted to `JSON` string
   # @return [String]
   def ruby_hash_to_json_string(hash)
     hash.to_json
   end
 
-  # @param  [String]
+  # @param  [String] `JSON` string to be converted to ruby `Hash`
   # @return [Hash]
   def json_string_to_ruby_hash(string)
     JSON.parse(string)
diff --git a/Library/Homebrew/linkage_cache_store.rb b/Library/Homebrew/linkage_cache_store.rb
index cb306b9089..fce17ecc05 100644
--- a/Library/Homebrew/linkage_cache_store.rb
+++ b/Library/Homebrew/linkage_cache_store.rb
@@ -21,10 +21,10 @@ class LinkageStore < CacheStore
   # Inserts dylib-related information into the cache if it does not exist or
   # updates data into the linkage cache if it does exist
   #
-  # @param  [Hash]        array_values
-  # @param  [Hash]        hash_values
+  # @param  [Hash] array_values: hash containing KVPs of { :type => Array | Set }
+  # @param  [Hash] hash_values:  hash containing KVPs of { :type => Hash }
   # @param  [Array[Hash]] values
-  # @raise  [TypeError]
+  # @raise  [TypeError] error if the values are not `Arary`, `Set`, or `Hash`
   # @return [nil]
   def update!(array_values: {}, hash_values: {}, **values)
     values.each do |key, value|
@@ -33,7 +33,10 @@ class LinkageStore < CacheStore
       elsif value.is_a?(Array) || value.is_a?(Set)
         array_values[key] = value
       else
-        raise TypeError, "Can't store types that are not `Array` or `Hash` in the linkage store."
+        raise TypeError, <<~EOS
+          Can't store types that are not `Array`, `Set` or `Hash` in the
+          linkage store.
+        EOS
       end
     end
 
@@ -44,7 +47,8 @@ class LinkageStore < CacheStore
   end
 
   # @param  [Symbol] the type to fetch from the `LinkageStore`
-  # @raise  [TypeError]
+  # @raise  [TypeError] error if the type is not in `HASH_LINKAGE_TYPES` or
+  #   `ARRAY_LINKAGE_TYPES`
   # @return [Hash | Array]
   def fetch_type(type)
     if HASH_LINKAGE_TYPES.include?(type)
@@ -52,7 +56,9 @@ class LinkageStore < CacheStore
     elsif ARRAY_LINKAGE_TYPES.include?(type)
       fetch_array_values(type)
     else
-      raise TypeError, "Can't fetch types that are not defined for the linkage store."
+      raise TypeError, <<~EOS
+        Can't fetch types that are not defined for the linkage store
+      EOS
     end
   end
 
@@ -63,10 +69,10 @@ class LinkageStore < CacheStore
 
   private
 
-  # @return [String]
+  # @return [String] the key to lookup items in the `CacheStore`
   attr_reader :keg_name
 
-  # @param  [Symbol] type
+  # @param  [Symbol] the type to fetch from the `LinkageStore`
   # @return [Array]
   def fetch_array_values(type)
     return [] unless database_cache.key?(keg_name)